fix worker_exists for SCC

src/core/workers.c

@@ -128,7 +128,7 @@ static uint32_t _starpu_worker_exists_and_can_execute(struct starpu_task *task,
 					test_implementation = 1;
 				break;
 			case STARPU_SCC_WORKER:
-				if (task->cl->cpu_funcs_name[impl] != NULL || task->cl->mic_funcs[impl] != NULL)
+				if (task->cl->cpu_funcs_name[impl] != NULL || task->cl->scc_funcs[impl] != NULL)
 					test_implementation = 1;
 				break;
 			default: