common: Drop image.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/fdt_region.c b/common/fdt_region.c
index bf0a9be..6676590 100644
--- a/common/fdt_region.c
+++ b/common/fdt_region.c
@@ -5,6 +5,7 @@
  * Written by Simon Glass <sjg@chromium.org>
  */
 
+#include <fdt_support.h>
 #include <linux/libfdt_env.h>
 #include <fdt_region.h>