Revert "Send ping to wake up new threads."

This reverts commit bf4c3626bc.

Prepare to rollback.

main.c

@@ -3396,10 +3396,6 @@ static void *reinit_gpu(void *userdata)
 
 	/* Try to re-enable it */
 	gpu_devices[gpu] = true;
-	for (thr_id = 0; thr_id < gpu_threads; thr_id ++) {
-		if (dev_from_id(thr_id) == gpu)
-			tq_push(thr->q, &ping);
-	}
 
 	return NULL;
 }