[media] DocBook: Move media-framework.txt contents to media-device.h

Instead of using a text file, let's put it together with the
struct documentation for the Media Controller.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Documentation/DocBook/device-drivers.tmpl

@@ -263,6 +263,7 @@ X!Isound/sound_firmware.c
 !Iinclude/media/lirc_dev.h
     </sect1>
     <sect1><title>Media Controller devices</title>
+!Pinclude/media/media-device.h Media Controller
 !Iinclude/media/media-device.h
 !Iinclude/media/media-devnode.h
 !Iinclude/media/media-entity.h