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/gateworks/gw_ventana/gw_ventana.c b/board/gateworks/gw_ventana/gw_ventana.c
index 6c81864..1443ef9 100644
--- a/board/gateworks/gw_ventana/gw_ventana.c
+++ b/board/gateworks/gw_ventana/gw_ventana.c
@@ -33,6 +33,7 @@
 #include <mtd_node.h>
 #include <netdev.h>
 #include <pci.h>
+#include <linux/libfdt.h>
 #include <power/pmic.h>
 #include <power/ltc3676_pmic.h>
 #include <power/pfuze100_pmic.h>