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/spl/spl_ubi.c b/common/spl/spl_ubi.c
index 0cb5080..de6a63b 100644
--- a/common/spl/spl_ubi.c
+++ b/common/spl/spl_ubi.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <config.h>
+#include <image.h>
 #include <nand.h>
 #include <onenand_uboot.h>
 #include <ubispl.h>