PCI: rcar: Add R8A7794 support

Add Renesas R8A7794 SoC support to the Renesas R-Car gen2 PCI driver.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/pci/pci-rcar-gen2.txt

@@ -7,7 +7,8 @@ OHCI and EHCI controllers.
 
 Required properties:
 - compatible: "renesas,pci-r8a7790" for the R8A7790 SoC;
-	      "renesas,pci-r8a7791" for the R8A7791 SoC.
+	      "renesas,pci-r8a7791" for the R8A7791 SoC;
+	      "renesas,pci-r8a7794" for the R8A7794 SoC.
 - reg:	A list of physical regions to access the device: the first is
 	the operational registers for the OHCI/EHCI controllers and the
 	second is for the bridge configuration and control registers.