[media] bt8xx: add support for Tongwei Video Technology TD-3116

The following patch adds support for the Tongwei Video Technology TD-3116 board. This
is a Bt878 based capture card with 16 inputs meant for surveilance applications.
It also offers a way to check which inputs have a video signal while capturing another
input. In addition there are a number of alarm inputs and outputs available and there
is microcontroller which is presumably intended for use as a system watchdog. None of
these extra capabilities are supported by the patch.

Signed-off-by: Peter De Schrijver <p2@psychaos.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>