Update mqtt.c

mqtt.c

@@ -35,7 +35,7 @@ int mqtt_init()
 {
  // 初始化 mosquitto 库
     mosquitto_lib_init();  
-    mosq = mosquitto_new(CLIENT_ID, true, NULL);
+    mosq = mosquitto_new(NULL, true, NULL);
     if (!mosq) {
         fprintf(stderr, "Failed to create Mosquitto client\n");
         return -1;