tools: gst-inspect: add * for pointer signal arguments where needed

tools: gst-inspect: add * for pointer signal arguments where needed

Print GObject argument properly with pointer marker:

  "client-added" :  void user_function (GstElement* object,
                                        GObject* arg0,
                                        gpointer user_data);

instead of

  "client-added" :  void user_function (GstElement* object,
                                        GObject arg0,
                                        gpointer user_data);

for gst-inspect-1.0 tcpserversink.