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 <[e-mail]>
Reviewed-by: Wolfram Sang <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/96aad[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

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

···
               - 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