ARM: shmobile: r8a7794: add PFC DT support

Define the generic R8A7794 part of the PFC device node.

Based on original patch by Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7794.dtsi

@@ -108,6 +108,12 @@ irqc0: interrupt-controller@e61c0000 {
 		clocks = <&mstp4_clks R8A7794_CLK_IRQC>;
 	};
 
+	pfc: pin-controller@e6060000 {
+		compatible = "renesas,pfc-r8a7794";
+		reg = <0 0xe6060000 0 0x11c>;
+		#gpio-range-cells = <3>;
+	};
+
 	dmac0: dma-controller@e6700000 {
 		compatible = "renesas,rcar-dmac";
 		reg = <0 0xe6700000 0 0x20000>;