arm64: dts: Add PMU node for APM X-Gene Storm SOC

This patch adds the PMU device tree node for APM X-Gene Storm SOC.
Signed-off-by: Vinayak Kale <vkale@apm.com>
Signed-off-by: Feng Kan <fkan@apm.com>

arch/arm64/boot/dts/apm/apm-storm.dtsi

@@ -97,6 +97,11 @@ timer {
 		clock-frequency = <50000000>;
 	};
 
+	pmu {
+		compatible = "apm,potenza-pmu", "arm,armv8-pmuv3";
+		interrupts = <1 12 0xff04>;
+	};
+
 	soc {
 		compatible = "simple-bus";
 		#address-cells = <2>;