ARM: dts: sun4i-a10: Add PMU node

This is necessary to use 'perf' for cache profiling etc.
Tested on cubieboard with 'perf stat echo foo'.
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm/boot/dts/sun4i-a10.dtsi

@@ -184,6 +184,11 @@ de: display-engine {
 		status = "disabled";
 	};
 
+	pmu {
+		compatible = "arm,cortex-a8-pmu";
+		interrupts = <3>;
+	};
+
 	soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;