arm/dts: OMAP2: Add support for OMAP2420H4 Board

Simple DTS file for OMAP2420H4 board adding memory information to allow
device-tree testing on an OMAP2420. OMAP2420H4 board has 64MB of RAM.

Verified that kernel boots with DT using a simple RAMDISK file-system on
OMAP2420H4.
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/omap2420-h4.dts

+/*
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+/dts-v1/;
+
+/include/ "omap2.dtsi"
+
+/ {
+	model = "TI OMAP2420 H4 board";
+	compatible = "ti,omap2420-h4", "ti,omap2420", "ti,omap2";
+
+	memory {
+		device_type = "memory";
+		reg = <0x80000000 0x84000000>; /* 64 MB */
+	};
+};