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/net/tftp.c b/net/tftp.c
index be24e63..3348521 100644
--- a/net/tftp.c
+++ b/net/tftp.c
@@ -11,6 +11,7 @@
 #include <efi_loader.h>
 #include <env.h>
 #include <image.h>
+#include <lmb.h>
 #include <mapmem.h>
 #include <net.h>
 #include <net/tftp.h>