V4L/DVB (7458): saa7134: Adds analog support for Avermedia A16D

Thanks to timf <timf@iinet.net.au>, "Richard (MQ)" <osl2008@googlemail.com> and
gian luca rasponi <lucarasp@inwind.it> for their tests.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>