arm64: dts: renesas: r8a779a0: Add DU support

Provide the device nodes for the DU on the V3U platforms.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20211126095445.932930-2-kieran.bingham+renesas@ideasonboard.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>