media: ov5640: add HFLIP/VFLIP controls support

Add HFLIP/VFLIP controls support by setting registers REG21/REG20.
Useless values in hardcoded mode sequences are removed and
remaining binning values are now set after mode sequence being set.
Note that due to BSI (Back Side Illuminated) technology, image capture
is physically mirrored, mirror logic is so inversed in REG21 register
to cancel this effect.

Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>