dt-bindings: dma: rz-dmac: Document RZ/V2H(P) family of SoCs

Document the Renesas RZ/V2H(P) family of SoCs DMAC block.
The Renesas RZ/V2H(P) DMAC is very similar to the one found on the
Renesas RZ/G2L family of SoCs, but there are some differences:
* It only uses one register area
* It only uses one clock
* It only uses one reset
* Instead of using MID/IRD it uses REQ No
* It is connected to the Interrupt Control Unit (ICU)

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250423143422.3747702-3-fabrizio.castro.jz@renesas.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>