ARM: dt: Add binding for Tegra PMC

The Tegra PMC (Power Management Controller) interfaces with an external
PMU (Power Management Unit), and controls wake-up from sleep modes.

This initial binding is the bare minimum required to control the PMC's
inversion of the PMU's interrupt signal.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
index 8712449..3195ad5 100644
--- a/arch/arm/boot/dts/tegra20.dtsi
+++ b/arch/arm/boot/dts/tegra20.dtsi
@@ -4,6 +4,11 @@
 	compatible = "nvidia,tegra20";
 	interrupt-parent = <&intc>;
 
+	pmc@7000f400 {
+		compatible = "nvidia,tegra20-pmc";
+		reg = <0x7000e400 0x400>;
+	};
+
 	intc: interrupt-controller@50041000 {
 		compatible = "arm,cortex-a9-gic";
 		interrupt-controller;