media: ov5640: fix restore of last mode set

[ Upstream commit 985cdcb08a0488558d1005139596b64d73bee267 ]

Mode setting depends on last mode set, in particular
because of exposure calculation when downscale mode
change between subsampling and scaling.
At stream on the last mode was wrongly set to current mode,
so no change was detected and exposure calculation
was not made, fix this.

Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Tested-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>