EKF: Add error macro when running into errors

src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp

@@ -1691,6 +1691,6 @@ int ekf_att_pos_estimator_main(int argc, char *argv[])
 		return ret;
 	}
 
-	PX4_WARN("unrecognized command");
+	PX4_ERR("unrecognized command");
 	return 1;
 }