Explicitly disable unsolicited messages for generic GSM modems.

src/mm-generic-gsm.c

@@ -157,9 +157,12 @@ init_done (MMSerial *serial,
     if (error) {
         info->error = g_error_copy (error);
         mm_callback_info_schedule (info);
-    } else
+    } else {
+        /* Disable unsolicited registration state changes, these will mess up our response parser */
+        mm_serial_queue_command (serial, "+CREG=0", 5, NULL, NULL);
         mm_serial_queue_command (serial, "+CFUN=1", 5, enable_done, user_data);
     }
+}
 
 static void
 enable_flash_done (MMSerial *serial, gpointer user_data)