V4L/DVB (12072): gspca-ov519: add extra controls

This patch adds autobrightness (so that it can
be turned off to make the already present brightness
control work) and light frequency filtering controls.

The lightfreq control needed 2 different entries
in the ctrls array, as the number of options differs
depending on the sensor. Always one of the 2 entires is
disabled ofcourse.

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