arm64: dts: renesas: r8a77980: add INTC-EX support

Describe the INTC-EX interrupt controller in the R8A77980 device tree.

Based on the original (and large) patch by Vladimir Barinov.
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77980.dtsi

@@ -234,6 +234,22 @@
 			#power-domain-cells = <1>;
 		};
 
+		intc_ex: interrupt-controller@e61c0000 {
+			compatible = "renesas,intc-ex-r8a77980", "renesas,irqc";
+			#interrupt-cells = <2>;
+			interrupt-controller;
+			reg = <0 0xe61c0000 0 0x200>;
+			interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH
+				      GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH
+				      GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH
+				      GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH
+				      GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH
+				      GIC_SPI 161 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&cpg CPG_MOD 407>;
+			power-domains = <&sysc R8A77980_PD_ALWAYS_ON>;
+			resets = <&cpg 407>;
+		};
+
 		i2c0: i2c@e6500000 {
 			compatible = "renesas,i2c-r8a77980",
 				     "renesas,rcar-gen3-i2c";