[media] media: tw686x: Rework initial hardware configuration

Currently, the hardware is not given a complete initial
configuration.

In order to fix this, this rather large commit reworks
standard, frame format and input configuration. While
at it, we introduce proper functions to configure
each parameter, and as a result the code is a bit cleaner.

Reported-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>