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/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi
index 8db792b..bbc8ed8 100644
--- a/arch/arm/boot/dts/exynos5420.dtsi
+++ b/arch/arm/boot/dts/exynos5420.dtsi
@@ -19,7 +19,7 @@
 #include <dt-bindings/clk/exynos-audss-clk.h>
 
 / {
-	compatible = "samsung,exynos5420";
+	compatible = "samsung,exynos5420", "samsung,exynos5";
 
 	aliases {
 		mshc0 = &mmc_0;