[media] DocBook/media: fix syntax error

Missing varlistentry tags.

Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/DocBook/media/v4l/vidioc-qbuf.xml

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 	</para>
 	</listitem>
+      </varlistentry>
+      <varlistentry>
 	<term><errorcode>EPIPE</errorcode></term>
 	<listitem>
 	  <para><constant>VIDIOC_DQBUF</constant> returns this on an empty
 capture queue for mem2mem codecs if a buffer with the
 <constant>V4L2_BUF_FLAG_LAST</constant> was already dequeued and no new buffers
 are expected to become available.
-	</para>
+	  </para>
 	</listitem>
       </varlistentry>
     </variablelist>