dts: samsung: arndale: Fix include path

As per new convention ARCH_CPU_DTS is not defined in "dtc/Makefile".
Hence Arndale comilation is failing. Fix this by adding proper include
file in "board/samsung/dts/exynos5250-arndale.dts".

Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/board/samsung/dts/exynos5250-arndale.dts b/board/samsung/dts/exynos5250-arndale.dts
index c700e45..202f2ea 100644
--- a/board/samsung/dts/exynos5250-arndale.dts
+++ b/board/samsung/dts/exynos5250-arndale.dts
@@ -8,7 +8,7 @@
 */
 
 /dts-v1/;
-/include/ ARCH_CPU_DTS
+#include "exynos5250.dtsi"
 
 / {
 	model = "SAMSUNG Arndale board based on EXYNOS5250";