ARM: dts: imx51: Add PMU support

Add PMU support in the device tree.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx51.dtsi

@@ -93,6 +93,12 @@
 		};
 	};
 
+	pmu: pmu {
+		compatible = "arm,cortex-a8-pmu";
+		interrupt-parent = <&tzic>;
+		interrupts = <77>;
+	};
+
 	usbphy0: usbphy0 {
 		compatible = "usb-nop-xceiv";
 		clocks = <&clks IMX5_CLK_USB_PHY_GATE>;