fix Wswitch

mpdws.c

@@ -73,6 +73,8 @@ static int ws_callback(struct lws *wsi, enum lws_callback_reasons reason,
       lws_write(wsi, &buf[LWS_PRE], msg_len, LWS_WRITE_TEXT);
     }
     break;
+  default:
+    break;
   }
   return 0;
 }