Show name of arch for which energy measurement could not be done

tests/perfmodels/regression_based_memset.c

@@ -213,7 +213,7 @@ static int bench_energy(int workerid, int where, enum starpu_worker_archtype arc
 		if ( (retval = starpu_energy_start(workerid, archtype)) != 0)
 		{
 			starpu_data_unregister(handle);
-			_STARPU_DISP("Energy measurement not supported for archtype %d\n", archtype);
+			_STARPU_DISP("Energy measurement not supported for archtype %s\n", starpu_perfmodel_get_archtype_name(archtype));
 			return -1;
 		}