arm64: dts: renesas: r8a77980: add Cortex-A53 PMU support

Describe the performance monitor unit (PMU) for the Cortex-A53 cores in
the R8A77980 SoC's device tree.

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

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

@@ -98,6 +98,15 @@ extalr_clk: extalr {
 		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>,
+				      <&gic GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+				      <&gic GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-affinity = <&a53_0>, <&a53_1>, <&a53_2>, <&a53_3>;
+	};
+
 	psci {
 		compatible = "arm,psci-1.0", "arm,psci-0.2";
 		method = "smc";