[media] cx88: fix a number of v4l2-compliance violations

- missing COMPRESSED flag for MPEG formats
- set colorspace
- set sizeimage
- add tuner index checks
- setup the frequency ranges correctly
- add missing g_chip_ident ioctl
- fix audmode handling
- don't handle vbi formats on a video node and vice versa.

cx88 now passes the v4l2-compliance tests.

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