dt-bindings: dma: rz-dmac: Document RZ/G3E family of SoCs

The DMAC block on the RZ/G3E SoC is identical to the one found on the
RZ/V2H(P) SoC.

No driver changes are required, as `renesas,r9a09g057-dmac` will be used
as a fallback compatible string on the RZ/G3E SoC.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20250801084825.471011-3-tommaso.merciai.xr@bp.renesas.com


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