Add definitions and documentation for the custom control that will be needed by the Mali-C55 ISP driver. This will be a read only bitmask of the driver's capabilities, informing userspace of which blocks are fitted and which are absent. Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>