V4L/DVB (7507): saa7134: add analog support for Avermedia A700 cards

Add support for composite and s-video inputs on
Avermedia DVB-S Pro and DVB-S Hybrid+FM cards
(both labled A700) to the saa7134 driver.

XC2028 support for Hybrid+FM is still missing.

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Reviewed-by: Hermann Pitton <hermann.pitton@arcor.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>