dt-bindings: PCI: rcar-gen4-pci-host: Add R-Car V4M compatible

Document bindings for R-Car V4M (R8A779H0) PCIe host module.

Link: https://lore.kernel.org/linux-pci/[e-mail]
Signed-off-by: Yoshihiro Shimoda <[e-mail]>
Signed-off-by: Krzysztof Wilczyński <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>

Documentation/devicetree/bindings/pci/rcar-gen4-pci-host.yaml

···
       - enum:
           - renesas,r8a779f0-pcie      # R-Car S4-8
           - renesas,r8a779g0-pcie      # R-Car V4H
+          - renesas,r8a779h0-pcie      # R-Car V4M
       - const: renesas,rcar-gen4-pcie  # R-Car Gen4
 
   reg: