ARM: dts: Update Exynos DT files with generic compatible strings

Add generic compatible strings to the respective board DT files.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/boot/dts/exynos4210.dtsi b/arch/arm/boot/dts/exynos4210.dtsi
index 48ecd7a..57131dc 100644
--- a/arch/arm/boot/dts/exynos4210.dtsi
+++ b/arch/arm/boot/dts/exynos4210.dtsi
@@ -23,7 +23,7 @@
 #include "exynos4210-pinctrl.dtsi"
 
 / {
-	compatible = "samsung,exynos4210";
+	compatible = "samsung,exynos4210", "samsung,exynos4";
 
 	aliases {
 		pinctrl0 = &pinctrl_0;