[media] DocBook media: fix awkward language in VIDIOC_QUERYCAP

Fix some awkward language in the VIDIOC_QUERYCAP description.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>