AP_Vehicle: add instructions for config_error loop

libraries/AP_Vehicle/AP_Vehicle.cpp

@@ -206,8 +206,12 @@ void AP_Vehicle::scheduler_delay_callback()
     }
     if (tnow - last_5s > 5000) {
         last_5s = tnow;
+        if (AP_BoardConfig::in_config_error()) {
+            gcs().send_text(MAV_SEVERITY_CRITICAL, "Config Error: fix problem then reboot");
+        } else {
             gcs().send_text(MAV_SEVERITY_INFO, "Initialising ArduPilot");
         }
+    }
 
     logger.EnableWrites(true);
 }