arm/versatile: Add the uart as the stdout device.

Add a stdout-path property to the Versatile devicetree so that automatic
console selection works without needing a console= line on the kernel
command line.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

arch/arm/boot/dts/versatile-ab.dts

@@ -15,6 +15,10 @@
 		i2c0 = &i2c0;
 	};
 
+	chosen {
+		stdout-path = &uart0;
+	};
+
 	memory {
 		reg = <0x0 0x08000000>;
 	};