V4L/DVB (13022): go7007: Fix mpeg controls

MPEG controls were disabled by Mauro's ioctl conversion patch.  They are now
re-enabled and cleaned up.

Signed-off-by: Pete Eberlein <pete@sensoray.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>