lmb: only force on arches that use it

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/image.h b/include/image.h
index dcf3a7b..4ed0379 100644
--- a/include/image.h
+++ b/include/image.h
@@ -256,7 +256,7 @@
 #define	BOOTM_STATE_OS_GO	(0x00000080)
 	int		state;
 
-#ifndef USE_HOSTCC
+#ifdef CONFIG_LMB
 	struct lmb	lmb;		/* for memory mgmt */
 #endif
 } bootm_headers_t;