[media] gspca_pac7302: avoid duplicate calls of the image quality adjustment functions on capturing start

There is no need to call the image quality adjustment functions in sd_start.
The gspca main driver calls v4l2_ctrl_handler_setup in gspca_init_transfer,
which already applies all image control values.
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>