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/arch/arm/lib/zimage.c b/arch/arm/lib/zimage.c
index 4930529..477ea94 100644
--- a/arch/arm/lib/zimage.c
+++ b/arch/arm/lib/zimage.c
@@ -7,6 +7,7 @@
  * Copyright (C) 2012 Marek Vasut <marek.vasut@gmail.com>
  */
 #include <common.h>
+#include <image.h>
 
 #define	LINUX_ARM_ZIMAGE_MAGIC	0x016f2818
 #define	BAREBOX_IMAGE_MAGIC	0x00786f62