[media] Mygica X8507 audio for YPbPr, AV and S-Video

Adds audio support for input YPbPr, AV and S-Video on Mygica X8507 card.

Remains to be done: IR, FM and ISDBT

Signed-off-by: Alfredo J. Delaiti <alfredodelaiti@netscape.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>