[media] gspca_zc3xx: Always automatically adjust BRC as needed

Always automatically adjust the Bit Rate Control setting as needed, independent
of the sensor type. BRC is needed to not run out of bandwidth with higher
quality settings independent of the sensor.

Also only automatically adjust BRC, and don't adjust the JPEG quality control
automatically, as that is not needed and leads to ugly flashes when it is
changed. Note that before this patch-set the quality was never changed
either due to the bugs in the quality handling fixed in previous patches in
this set.

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