arm64: dts: renesas: r8a77970: Add Cortex-A53 PMU node

Enable the performance monitor unit for the Cortex-A53 cores on the
R-Car V3M (r8a77970) SoC.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a77970.dtsi

@@ -73,6 +73,13 @@
 		clock-frequency = <0>;
 	};
 
+	pmu_a53 {
+		compatible = "arm,cortex-a53-pmu";
+		interrupts-extended = <&gic GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+				      <&gic GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-affinity = <&a53_0>, <&a53_1>;
+	};
+
 	psci {
 		compatible = "arm,psci-1.0", "arm,psci-0.2";
 		method = "smc";