ARM: dts: imx6q: add PMU

Add ARM Cortex A9 Performance Monitor Unit (PMU) support.
On i.MX6 a combined interrupt on hardware line #126 is used
(i.MX6 TRM: Performance Unit interrupt).

For more details see Documentation/devicetree/bindings/arm/pmu.txt
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx6qdl.dtsi

@@ -101,6 +101,11 @@ L2: l2-cache@00a02000 {
 			cache-level = <2>;
 		};
 
+		pmu {
+			compatible = "arm,cortex-a9-pmu";
+			interrupts = <0 94 0x04>;
+		};
+
 		aips-bus@02000000 { /* AIPS1 */
 			compatible = "fsl,aips-bus", "simple-bus";
 			#address-cells = <1>;