arm64: dts: renesas: r8a77961: Add INTC-EX device node

Populate the device node for the Interrupt Controller for External
Devices (INTC-EX) on R-Car M3-W+, which serves external IRQ pins
IRQ[0-5].
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/6f3cc1a1b6d777e743a7a9e66a80aaf9d5232a4f.1622547125.git.geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a77961.dtsi

@@ -560,10 +560,19 @@ tsc: thermal@e6198000 {
 		};
 
 		intc_ex: interrupt-controller@e61c0000 {
+			compatible = "renesas,intc-ex-r8a77961", "renesas,irqc";
 			#interrupt-cells = <2>;
 			interrupt-controller;
 			reg = <0 0xe61c0000 0 0x200>;
-			/* placeholder */
+			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 R8A77961_PD_ALWAYS_ON>;
+			resets = <&cpg 407>;
 		};
 
 		tmu0: timer@e61e0000 {