[swarm docker] Add major 189 back

Fastboot needs 180 and 189.

Change-Id: I09041062b5bd7ba14310c23b0f9520955710e2d7
diff --git a/cmd/swarm_docker/swarm_docker.go b/cmd/swarm_docker/swarm_docker.go
index 4ab1b44..593c7ee 100644
--- a/cmd/swarm_docker/swarm_docker.go
+++ b/cmd/swarm_docker/swarm_docker.go
@@ -122,7 +122,7 @@
 func (d *dockerPermissionWriter) writePermissions(ctx context.Context, id string) error {
 	path := fmt.Sprintf("%s/%s/devices.allow", d.dockerPermissionsFolder, id)
 	log.Printf("Attempting to write serial permissions to %s", path)
-	return ioutil.WriteFile(path, []byte("c 188:* rwm\nc 180:* rwm"), 0666)
+	return ioutil.WriteFile(path, []byte("c 188:* rwm\nc 180:* rwm\nc 189:* rwm"), 0666)
 }
 
 // Pool is used to manage a static pool of container instances.