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/toradex/apalis_imx6/apalis_imx6.c b/board/toradex/apalis_imx6/apalis_imx6.c
index 4792556..dac9503 100644
--- a/board/toradex/apalis_imx6/apalis_imx6.c
+++ b/board/toradex/apalis_imx6/apalis_imx6.c
@@ -9,6 +9,7 @@
 #include <common.h>
 #include <cpu_func.h>
 #include <dm.h>
+#include <image.h>
 #include <init.h>
 #include <net.h>