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_atf.c b/common/spl/spl_atf.c
index bc2921c..b83e3bb 100644
--- a/common/spl/spl_atf.c
+++ b/common/spl/spl_atf.c
@@ -13,6 +13,7 @@
 #include <atf_common.h>
 #include <cpu_func.h>
 #include <errno.h>
+#include <image.h>
 #include <spl.h>
 #include <asm/cache.h>