media: ov7740: fix vertical flip control

Setting the value of the V4L2_CID_VFLIP control is currently ignored.

Because V4L2_CID_HFLIP and V4L2_CID_VFLIP are independently controlled
in s_ctrl() but these controls belong to the same cluster and the first
control is V4L2_CID_HFLIP.

Fix it by not clustering these controls.  Also correct erroneous updating
register bit for vertical flip.

Cc: Wenyou Yang <wenyou.yang@microchip.com>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>