image.h: avoid command.h for host tools

The u-boot command structures don't get used with host systems, so don't
bother including it when building host code.  This avoids an implicit need
on config.h in the process.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

include/image.h

@@ -46,11 +46,10 @@
 
 #include <lmb.h>
 #include <asm/u-boot.h>
+#include <command.h>
 
 #endif /* USE_HOSTCC */
 
-#include <command.h>
-
 #if defined(CONFIG_FIT)
 #include <fdt.h>
 #include <libfdt.h>