isdn: fix a few Kconfig imperfections

1. Rewrite the outdated help texts for config options ISDN and ISDN_CAPI.
2. The MISDN config option appeared between ISDN_I4L and the I4L hardware
driver options; move it to a less irritating place.
3. HYSDN is not in fact an I4L driver, and needn't depend on ISDN_I4L, so
move it from the I4L section to the general section.
4. ISDN_HDLC is now also used by drivers outside I4L. Move it from the
I4L section to the general section, too.

Signed-off-by: Tilman Schmidt <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/isdn/Kconfig

···
 	depends on NET
 	depends on !S390
 	---help---
-	  ISDN ("Integrated Services Digital Networks", called RNIS in France)
-	  is a special type of fully digital telephone service; it's mostly
-	  used to connect to your Internet service provider (with SLIP or
-	  PPP).  The main advantage is that the speed is higher than ordinary
-	  modem/telephone connections, and that you can have voice
-	  conversations while downloading stuff.  It only works if your
-	  computer is equipped with an ISDN card and both you and your service
-	  provider purchased an ISDN line from the phone company.  For
-	  details, read <http://www.alumni.caltech.edu/~dank/isdn/> on the WWW.
+	  ISDN ("Integrated Services Digital Network", called RNIS in France)
+	  is a fully digital telephone service that can be used for voice and
+	  data connections.  If your computer is equipped with an ISDN
+	  adapter you can use it to connect to your Internet service provider
+	  (with SLIP or PPP) faster than via a conventional telephone modem
+	  (though still much slower than with DSL) or to make and accept
+	  voice calls (eg. turning your PC into a software answering machine
+	  or PABX).
 
 	  Select this option if you want your kernel to support ISDN.
 
···
 	  It is still available, though, for use with adapters that are not
 	  supported by the new CAPI subsystem yet.
 
-source "drivers/isdn/mISDN/Kconfig"
-
 source "drivers/isdn/i4l/Kconfig"
 
 menuconfig ISDN_CAPI
 	tristate "CAPI 2.0 subsystem"
 	help
-	  This provides the CAPI (Common ISDN Application Programming
-	  Interface, a standard making it easy for programs to access ISDN
-	  hardware, see <http://www.capi.org/>.  This is needed for AVM's set
-	  of active ISDN controllers like B1, T1, M1.
+	  This provides CAPI (the Common ISDN Application Programming
+	  Interface) Version 2.0, a standard making it easy for programs to
+	  access ISDN hardware in a device independent way. (For details see
+	  <http://www.capi.org/>.)  CAPI supports making and accepting voice
+	  and data connections, controlling call options and protocols,
+	  as well as ISDN supplementary services like call forwarding or
+	  three-party conferences (if supported by the specific hardware
+	  driver).
+
+	  Select this option and the appropriate hardware driver below if
+	  you have an ISDN adapter supported by the CAPI subsystem.
 
 if ISDN_CAPI
 
···
 endif # ISDN_CAPI
 
 source "drivers/isdn/gigaset/Kconfig"
+
+source "drivers/isdn/hysdn/Kconfig"
+
+source "drivers/isdn/mISDN/Kconfig"
+
+config ISDN_HDLC
+	tristate
+	select CRC_CCITT
+	select BITREVERSE
 
 endif # ISDN

drivers/isdn/i4l/Kconfig

···
 
 source "drivers/isdn/act2000/Kconfig"
 
-source "drivers/isdn/hysdn/Kconfig"
-
 endmenu
 # end ISDN_I4L
 endif
-
-config ISDN_HDLC
-	tristate
-	select CRC_CCITT
-	select BITREVERSE