V4L/DVB (12587): Add support BeholdTV X7 card

Add support our new TV card based on xc5000 and saa7134.
Analog TV works well.

Signed-off-by: Beholder Intl. Ltd. Dmitry Belimov <d.belimov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>