[media] bt819/saa7110/vpx3220: remove legacy control ops

The zoran driver has now been converted to the control framework
which means that these three subdevice drivers no longer need to
support the legacy core control ops since the last bridge driver
that needed that has now been converted.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>