V4L/DVB (12090): gspca_sonixj: enable autogain control for the ov7620

gspca_sonixj: enable autogain control for the ov7620, and not only
make it enable autogain but also auto exposure (and do the
same for the ov7648).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>