dt-bindings: renesas,rcar-dmac: Add r8a779h0 support

Document support for the Direct Memory Access Controllers (DMAC) in the
Renesas R-Car V4M (R8A779H0) SoC.

Based on a patch in the BSP by Thanh Le.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/96aad3b532ee401f19693e18038494f43ddb90e9.1707915609.git.geert+renesas@glider.beSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/renesas,rcar-dmac.yaml

@@ -46,6 +46,7 @@ properties:
               - renesas,dmac-r8a779a0     # R-Car V3U
               - renesas,dmac-r8a779f0     # R-Car S4-8
               - renesas,dmac-r8a779g0     # R-Car V4H
+              - renesas,dmac-r8a779h0     # R-Car V4M
           - const: renesas,rcar-gen4-dmac # R-Car Gen4
 
   reg: true