V4L/DVB (3269): ioctls cleanups.

- Now, all internal ioctls are at v4l2-common.h
- removed unused ioctl at saa6752hs.h
- all debug ioctl code moved to v4l2-common.c
- removed duplicated stuff from other cards

Signed-off-by: Michael Krufky <mkrufky@m1k.net>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>