media: dt-bindings: media: renesas,vsp1: Document RZ/G2UL VSPD bindings

media: dt-bindings: media: renesas,vsp1: Document RZ/G2UL VSPD bindings

Document VSPD found in RZ/G2UL SoC. The VSPD block is identical to RZ/G2L
SoC and therefore use RZ/G2L fallback to avoid any driver changes.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>