[media] V4L DocBook: update V4L2 version

Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/v4l/v4l2.xml

@@ -410,7 +410,7 @@ and discussions on the V4L mailing list.</revremark>
 </partinfo>
 
 <title>Video for Linux Two API Specification</title>
- <subtitle>Revision 2.6.38</subtitle>
+ <subtitle>Revision 2.6.39</subtitle>
 
   <chapter id="common">
     &sub-common;