V4L/DVB (8483): Remove obsolete owner field from video_device struct.

According to an old comment this should have been removed in 2.6.15.
Better late than never...

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>