Define a PixelFormat type as a simple typedef to an uint32_t. The usage of a dedicated type creates a cleaner and more self-described API. Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>