media: i2c: ov5647: use our own mutex for the ctrl lock

media: i2c: ov5647: use our own mutex for the ctrl lock

__v4l2_ctrl_handler_setup() and __v4l2_ctrl_modify_range() contains an
assertion to verify that the v4l2_ctrl_handler::lock is held, as it should
only be called when the lock has already been acquired. Therefore use our
own mutex for the ctrl lock, otherwise a warning will be reported.

Fixes: 4974c2f19fd8 ("media: ov5647: Support gain, exposure and AWB controls")
Cc: stable@vger.kernel.org
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
[Sakari Ailus: Fix a minor conflict.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>