arm: dts: ti_lm3s6965: Add Device Tree Support

Introduce a simple device tree for the TI lm3s6965 SoC and QEMU
Cortex-M3 board port.  We get flash and memory base addresses and sizes
from the device tree as well as the ARM NVIC number of priority bits.

Change-Id: I4452b5543de7be55518997e54837ccbfd4f121df
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

dts/arm/ti/lm3s6965.dtsi

@@ -0,0 +1,25 @@
+#include <arm/armv7-m.dtsi>
+
+/ {
+	cpus {
+		cpu@0 {
+			compatible = "arm,cortex-m3";
+		};
+	};
+
+	sram0: memory {
+		compatible = "sram";
+		reg = <0x20000000 (64*1024)>;
+	};
+
+	flash0: flash {
+		reg = <0x00000000 (256*1024)>;
+	};
+
+	soc {
+	};
+};
+
+&nvic {
+	arm,num-irq-priority-bits = <3>;
+};