media: drm: rcar-du: Add support for CRC computation

Implement CRC computation configuration and reporting through the DRM
debugfs-based CRC API. The CRC source can be configured to any input
plane or the pipeline output.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>