fdt: tegra: Add EMC node to device tree

Add a definition of the memory controller node according to the bindings
here:

http://patchwork.ozlabs.org/patch/132928/

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/dts/tegra20.dtsi

@@ -193,4 +193,11 @@
 		clocks = <&tegra_car 59>;	/* PERIPH_ID_USB3 */
 	};
 
+	emc@7000f400 {
+		#address-cells = < 1 >;
+		#size-cells = < 0 >;
+		compatible = "nvidia,tegra20-emc";
+		reg = <0x7000f400 0x200>;
+	};
+
 };