[media] DocBook: Use constant tag for monospaced fonts

As reminded by Jonathan, several places where emphasys
role="tt" were used are actually trying to change the font to
monospaced.

We do that, on other places, by using the constant tag.

So, use it here too.

Reported-by: Jonathan Corbet <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/DocBook/media/dvb/audio.xml

···
 <title>DVB Audio Device</title>
 <para>The DVB audio device controls the MPEG2 audio decoder of the DVB hardware. It
-can be accessed through <emphasis role="bold">/dev/dvb/adapter0/audio0</emphasis>. Data types and and
-ioctl definitions can be accessed by including <emphasis role="bold">linux/dvb/audio.h</emphasis> in your
+can be accessed through <constant>/dev/dvb/adapter?/audio?</constant>. Data types and and
+ioctl definitions can be accessed by including <constant>linux/dvb/audio.h</constant> in your
 application.
 </para>
 <para>Please note that some DVB cards don&#8217;t have their own MPEG decoder, which results in
···
 </programlisting>
 <para>AUDIO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the
 DVR device) as the source of the video stream. If AUDIO_SOURCE_MEMORY
-is selected the stream comes from the application through the <emphasis role="bold">write()</emphasis> system
+is selected the stream comes from the application through the <constant>write()</constant> system
 call.
 </para>
 

Documentation/DocBook/media/dvb/ca.xml

···
 <title>DVB CA Device</title>
 <para>The DVB CA device controls the conditional access hardware. It can be accessed through
-<emphasis role="bold">/dev/dvb/adapter0/ca0</emphasis>. Data types and and ioctl definitions can be accessed by
-including <emphasis role="bold">linux/dvb/ca.h</emphasis> in your application.
+<constant>/dev/dvb/adapter?/ca?</constant>. Data types and and ioctl definitions can be accessed by
+including <constant>linux/dvb/ca.h</constant> in your application.
 </para>
 
 <section id="ca_data_types">

Documentation/DocBook/media/dvb/demux.xml

···
 <title>DVB Demux Device</title>
 
 <para>The DVB demux device controls the filters of the DVB hardware/software. It can be
-accessed through <emphasis role="bold">/dev/adapter0/demux0</emphasis>. Data types and and ioctl definitions can be
-accessed by including <emphasis role="bold">linux/dvb/dmx.h</emphasis> in your application.
+accessed through <constant>/dev/adapter?/demux?</constant>. Data types and and ioctl definitions can be
+accessed by including <constant>linux/dvb/dmx.h</constant> in your application.
 </para>
 <section id="dmx_types">
 <title>Demux Data Types</title>
···
 	DMX_OUT_TSDEMUX_TAP /&#x22C6; Like TS_TAP but retrieved from the DMX device &#x22C6;/
 } dmx_output_t;
 </programlisting>
-<para><emphasis role="bold">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is
+<para><constant>DMX_OUT_TAP</constant> delivers the stream output to the demux device on which the ioctl is
 called.
 </para>
-<para><emphasis role="bold">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="bold">/dev/dvb/adapter0/dvr0</emphasis>,
-which delivers a TS multiplexed from all filters for which <emphasis role="bold">DMX_OUT_TS_TAP</emphasis> was
+<para><constant>DMX_OUT_TS_TAP</constant> routes output to the logical DVR device <constant>/dev/dvb/adapter?/dvr?</constant>,
+which delivers a TS multiplexed from all filters for which <constant>DMX_OUT_TS_TAP</constant> was
 specified.
 </para>
 </section>

Documentation/DocBook/media/dvb/frontend.xml

···
     <listitem><para>Satellite Equipment Control (SEC) hardware (only for Satellite).</para></listitem>
 </itemizedlist>
 <para>The frontend can be accessed through
-    <emphasis role="bold">/dev/dvb/adapter?/frontend?</emphasis>. Data types and
+    <constant>/dev/dvb/adapter?/frontend?</constant>. Data types and
     ioctl definitions can be accessed by including
-    <emphasis role="bold">linux/dvb/frontend.h</emphasis> in your application.
+    <constant>linux/dvb/frontend.h</constant> in your application.
 </para>
 
 <para>NOTE: Transmission via the internet (DVB-IP)

Documentation/DocBook/media/dvb/intro.xml

···
 platform, if and how many of the CA functions are made available to the
 application through this device.</para>
 
-<para>All devices can be found in the <emphasis role="bold">/dev</emphasis>
-tree under <emphasis role="bold">/dev/dvb</emphasis>. The individual devices
+<para>All devices can be found in the <constant>/dev</constant>
+tree under <constant>/dev/dvb</constant>. The individual devices
 are called:</para>
 
 <itemizedlist>
 <listitem>
 
-<para><emphasis role="bold">/dev/dvb/adapterN/audioM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/audioM</constant>,</para>
 </listitem>
 <listitem>
-<para><emphasis role="bold">/dev/dvb/adapterN/videoM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/videoM</constant>,</para>
 </listitem>
 <listitem>
-<para><emphasis role="bold">/dev/dvb/adapterN/frontendM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/frontendM</constant>,</para>
 </listitem>
  <listitem>
 
-<para><emphasis role="bold">/dev/dvb/adapterN/netM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/netM</constant>,</para>
 </listitem>
  <listitem>
 
-<para><emphasis role="bold">/dev/dvb/adapterN/demuxM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/demuxM</constant>,</para>
 </listitem>
  <listitem>
 
-<para><emphasis role="bold">/dev/dvb/adapterN/dvrM</emphasis>,</para>
+<para><constant>/dev/dvb/adapterN/dvrM</constant>,</para>
 </listitem>
  <listitem>
 
-<para><emphasis role="bold">/dev/dvb/adapterN/caM</emphasis>,</para></listitem></itemizedlist>
+<para><constant>/dev/dvb/adapterN/caM</constant>,</para></listitem></itemizedlist>
 
 <para>where N enumerates the DVB PCI cards in a system starting
 from&#x00A0;0, and M enumerates the devices of each type within each
-adapter, starting from&#x00A0;0, too. We will omit the &#8220;<emphasis
-role="bold">/dev/dvb/adapterN/</emphasis>&#8221; in the further dicussion
+adapter, starting from&#x00A0;0, too. We will omit the &#8220;
+<constant>/dev/dvb/adapterN/</constant>&#8221; in the further dicussion
 of these devices. The naming scheme for the devices is the same wheter
 devfs is used or not.</para>
 
···
 </programlisting>
 
 <para>To enable applications to support different API version, an
-additional include file <emphasis
-role="bold">linux/dvb/version.h</emphasis> exists, which defines the
-constant <emphasis role="bold">DVB_API_VERSION</emphasis>. This document
-describes <emphasis role="bold">DVB_API_VERSION 5.10</emphasis>.
+additional include file
+<constant>linux/dvb/version.h</constant> exists, which defines the
+constant <constant>DVB_API_VERSION</constant>. This document
+describes <constant>DVB_API_VERSION 5.10</constant>.
 </para>
 
 </section>

Documentation/DocBook/media/dvb/kdapi.xml

···
 <title>Kernel Demux API</title>
 <para>The kernel demux API defines a driver-internal interface for registering low-level,
 hardware specific driver to a hardware independent demux layer. It is only of interest for
-DVB device driver writers. The header file for this API is named <emphasis role="bold">demux.h</emphasis> and located in
-<emphasis role="bold">drivers/media/dvb-core</emphasis>.
+DVB device driver writers. The header file for this API is named <constant>demux.h</constant> and located in
+<constant>">drivers/media/dvb-core</constant>.
 </para>
 <para>Maintainer note: This section must be reviewed. It is probably out of date.
 </para>

Documentation/DocBook/media/dvb/net.xml

···
 <para>In order to create the Linux virtual network interfaces, an application
     needs to tell to the Kernel what are the PIDs and the encapsulation types
     that are present on the transport stream. This is done through
-    <emphasis role="bold">/dev/dvb/adapter?/net?</emphasis> device node.
+    <constant>/dev/dvb/adapter?/net?</constant> device node.
     The data will be available via virtual <constant>dvb?_?</constant>
     network interfaces, and will be controled/routed via the standard
     ip tools (like ip, route, netstat, ifconfig, etc).</para>
 <para> Data types and and ioctl definitions are defined via
-    <emphasis role="bold">linux/dvb/net.h</emphasis> header.</para>
+    <constant>linux/dvb/net.h</constant> header.</para>
 
 <section id="net_fcalls">
 <title>DVB net Function Calls</title>

Documentation/DocBook/media/dvb/video.xml

···
 
 <section id="video-format-t">
 <title>video_format_t</title>
-<para>The <emphasis role="bold">video_format_t</emphasis> data type defined by
+<para>The <constant>video_format_t</constant> data type defined by
 </para>
 <programlisting>
 typedef enum {