media: i2c: ov5645: Use subdev active state

Port the ov5645 sensor driver to use the subdev active state.

Move all the format configuration to the subdevice state and simplify
the format handling, locking and initialization.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>