common: Drop linux/stringify.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/exynos-common.h b/include/configs/exynos-common.h
index 5ae2b42..bb34a9e 100644
--- a/include/configs/exynos-common.h
+++ b/include/configs/exynos-common.h
@@ -14,6 +14,7 @@
 
 #include <asm/arch/cpu.h>		/* get chip and board defs */
 #include <linux/sizes.h>
+#include <linux/stringify.h>
 
 #define CONFIG_SKIP_LOWLEVEL_INIT