libfdt: move FDT_RAMDISK_OVERHEAD to image-fdt.c

This macro is locally referenced in common/image-fdt.c

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/image-fdt.c b/common/image-fdt.c
index 25103ba..3dc02a1 100644
--- a/common/image-fdt.c
+++ b/common/image-fdt.c
@@ -21,6 +21,9 @@
 #define CONFIG_SYS_FDT_PAD 0x3000
 #endif
 
+/* adding a ramdisk needs 0x44 bytes in version 2008.10 */
+#define FDT_RAMDISK_OVERHEAD	0x80
+
 DECLARE_GLOBAL_DATA_PTR;
 
 static void fdt_error(const char *msg)
diff --git a/include/linux/libfdt.h b/include/linux/libfdt.h
index 9e6eead..eeb2344 100644
--- a/include/linux/libfdt.h
+++ b/include/linux/libfdt.h
@@ -309,7 +309,4 @@
 
 extern struct fdt_header *working_fdt;  /* Pointer to the working fdt */
 
-/* adding a ramdisk needs 0x44 bytes in version 2008.10 */
-#define FDT_RAMDISK_OVERHEAD	0x80
-
 #endif /* _INCLUDE_LIBFDT_H_ */