arm/dt: Tegra: Add pinmux node to tegra20.dtsi

Add a pinmux node to tegra20.dtsi in order to instantiate the future
pinmux device.

v2: Specify reg property precisely; don't just point at the whole APB_MISC
register range.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Documentation/devicetree/bindings/pinmux/pinmux_nvidia.txt

+NVIDIA Tegra 2 pinmux controller
+
+Required properties:
+- compatible : "nvidia,tegra20-pinmux"
+

arch/arm/boot/dts/tegra20.dtsi

@@ -77,6 +77,14 @@ gpio: gpio@6000d000 {
 		gpio-controller;
 	};
 
+	pinmux: pinmux@70000000 {
+		compatible = "nvidia,tegra20-pinmux";
+		reg = < 0x70000014 0x10    /* Tri-state registers */
+			0x70000080 0x20    /* Mux registers */
+			0x700000a0 0x14    /* Pull-up/down registers */
+			0x70000868 0xa8 >; /* Pad control registers */
+	};
+
 	serial@70006000 {
 		compatible = "nvidia,tegra20-uart";
 		reg = <0x70006000 0x40>;