ARM: dts: r8a73a4: Add device node for PRR

Add a device node for the Product Register, which provides SoC product
and revision information.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a73a4.dtsi

@@ -751,6 +751,11 @@
 		};
 	};
 
+	prr: chipid@ff000044 {
+		compatible = "renesas,prr";
+		reg = <0 0xff000044 0 4>;
+	};
+
 	sysc: system-controller@e6180000 {
 		compatible = "renesas,sysc-r8a73a4", "renesas,sysc-rmobile";
 		reg = <0 0xe6180000 0 0x8000>, <0 0xe6188000 0 0x8000>;