V4L/DVB (12078): gspca_ov519: Better default contrast for ov6630

Hmm, another one with an extra if (life sucks) the
default contrast really is no good for the ov6630, it
isn't even high enough in full daylight, this gives
the ov6630 a different initial value for a better out
of the box experience.

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