tools/virtio: include asm/bug.h

WARN_ON is used in drivers/vhost/vringh.c, to avoid build failure,
need include asm/bug.h
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20201209084205.24062-2-peng.fan@oss.nxp.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

tools/virtio/linux/bug.h

@@ -2,6 +2,8 @@
 #ifndef BUG_H
 #define BUG_H
 
+#include <asm/bug.h>
+
 #define BUG_ON(__BUG_ON_cond) assert(!(__BUG_ON_cond))
 
 #define BUILD_BUG_ON(x)