drm: rcar-du: Add support for missing pixel formats

This patch supports pixel format of RGB332, ARGB4444, XRGB4444,
BGR888, RGB888, BGRA8888, BGRX8888 and YVYU.
VYUY pixel format is not supported by H/W specification.

Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[Reordered formats with RGB first]
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>