media: gspca_zc3xx: Fix power line frequency settings for OV7648

Power line frequency settings for OV7648 sensor contain autogain
and exposure commands, affecting unrelated controls. Remove them.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>