arm/dts: Add omap36xx.dtsi file and rename omap3-beagle to omap3-beagle-xm

The extra serial port is not available on 34xx. And the current
omap3-beagle.dts file is for omap3-beagle-xm.dts as it lists 512MB
of memory.

Please somebody submit a new omap3-beagle.dts for the original 34xx
BeagleBoard after testing it properly.

Cc: Benoit Cousson <b-cousson@ti.com>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/boot/dts/omap36xx.dtsi b/arch/arm/boot/dts/omap36xx.dtsi
new file mode 100644
index 0000000..96bf028
--- /dev/null
+++ b/arch/arm/boot/dts/omap36xx.dtsi
@@ -0,0 +1,25 @@
+/*
+ * Device Tree Source for OMAP3 SoC
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+/include/ "omap3.dtsi"
+
+/ {
+	aliases {
+		serial3 = &uart4;
+	};
+
+	ocp {
+		uart4: serial@49042000 {
+			compatible = "ti,omap3-uart";
+			ti,hwmods = "uart4";
+			clock-frequency = <48000000>;
+		};
+	};
+};