dt-bindings: dma: rz-dmac: Document RZ/G3S SoC

Document the Renesas RZ/G3S DMAC block. This is identical to the one found
on the RZ/G2L SoC.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20240711123405.2966302-3-claudiu.beznea.uj@bp.renesas.com


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