dt-bindings: display: renesas,rzg2l-du: Add support for RZ/V2N SoC

dt-bindings: display: renesas,rzg2l-du: Add support for RZ/V2N SoC

Document support for the DU IP found on the Renesas RZ/V2N (R9A09G056) SoC.
The DU IP is functionally identical to that on the RZ/V2H(P) SoC, so no
driver changes are needed. The existing `renesas,r9a09g057-du` compatible
will be used as a fallback for the RZ/V2N SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20251023213350.681602-1-prabhakar.mahadev-lad.rj@bp.renesas.com