ARM: dts: socfpga: Add support for PMU

The dual Cortex-A9 MPCore inside socfpga has a standard PMU unit for
each core mapped in the DAP memory space. Add support for it!

Tested with perf on a Cyclone 5 SoC DK.
Reported-by: Alberto Dassatti <alberto.dassatti@heig-vd.ch>
Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>
Tested-by: Alberto Dassatti <alberto.dassatti@heig-vd.ch>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

arch/arm/boot/dts/socfpga.dtsi

@@ -51,6 +51,15 @@ cpu1: cpu@1 {
 		};
 	};
 
+	pmu: pmu@ff111000 {
+		compatible = "arm,cortex-a9-pmu";
+		interrupt-parent = <&intc>;
+		interrupts = <0 176 4>, <0 177 4>;
+		interrupt-affinity = <&cpu0>, <&cpu1>;
+		reg = <0xff111000 0x1000>,
+		      <0xff113000 0x1000>;
+	};
+
 	intc: intc@fffed000 {
 		compatible = "arm,cortex-a9-gic";
 		#interrupt-cells = <3>;