This adds helpers to deal with the conversion from StreamConfiguration to caps and vice-versa. This is needed to implement caps negotiation. Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>