dt-bindings: PCI: rcar: Add device tree support for r8a7743

Add support for r8a7743. The Renesas RZ/G1M(R8A7743)PCIe controller
is identical to the R-Car Gen2 family.

No driver change is needed due to the fallback compatible value
"renesas,pcie-rcar-gen2".
Adding the SoC-specific compatible values here has three purposes:
1. Document which SoCs have this hardware module,
2. Allow checkpatch to validate compatible values.
3. Allow the driver to support SoC specific implementations in future
   as necessary.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/pci/rcar-pci.txt

 * Renesas R-Car PCIe interface
 
 Required properties:
-compatible: "renesas,pcie-r8a7779" for the R8A7779 SoC;
+compatible: "renesas,pcie-r8a7743" for the R8A7743 SoC;
+	    "renesas,pcie-r8a7779" for the R8A7779 SoC;
 	    "renesas,pcie-r8a7790" for the R8A7790 SoC;
 	    "renesas,pcie-r8a7791" for the R8A7791 SoC;
 	    "renesas,pcie-r8a7793" for the R8A7793 SoC;
 	    "renesas,pcie-r8a7795" for the R8A7795 SoC;
 	    "renesas,pcie-r8a7796" for the R8A7796 SoC;
-	    "renesas,pcie-rcar-gen2" for a generic R-Car Gen2 compatible device.
+	    "renesas,pcie-rcar-gen2" for a generic R-Car Gen2 or
+				     RZ/G1 compatible device.
 	    "renesas,pcie-rcar-gen3" for a generic R-Car Gen3 compatible device.
 
 	    When compatible with the generic version, nodes must list the