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/board/ti/am335x/board.c b/board/ti/am335x/board.c
index c6de860..56fe171 100644
--- a/board/ti/am335x/board.c
+++ b/board/ti/am335x/board.c
@@ -11,6 +11,7 @@
 #include <dm.h>
 #include <env.h>
 #include <errno.h>
+#include <image.h>
 #include <init.h>
 #include <malloc.h>
 #include <net.h>