V4L/DVB (13197): gspca - sonixj: Adjust colors and autogain for sensor om6802.

- set correct colors at startup time
- autogain was too slow (4-5 mn - now 15-30 s))

Signed-off-by: Amauri Magagna <amaurimagagna@gmail.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>