ARM: dts: Fill in bootargs for exynos5250-snow

exynos5250-cros-common.dtsi had an empty /chosen node.
Fill in exemplary boot arguments.
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
Signed-off-by: NAndreas Faerber <afaerber@suse.de>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos5250-snow.dts

@@ -27,6 +27,7 @@
 	};
 
 	chosen {
+		bootargs = "console=tty1";
 	};
 
 	gpio-keys {