gpu: ion: dereferencing an ERR_PTR

We dereference "heap->task" before checking if it's an ERR_PTR.

Fixes: ea313b5f88 ('gpu: ion: Also shrink memory cached in the deferred free list')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion_heap.c

@@ -243,12 +243,12 @@ int ion_heap_init_deferred_free(struct ion_heap *heap)
 	init_waitqueue_head(&heap->waitqueue);
 	heap->task = kthread_run(ion_heap_deferred_free, heap,
 				 "%s", heap->name);
-	sched_setscheduler(heap->task, SCHED_IDLE, &param);
 	if (IS_ERR(heap->task)) {
 		pr_err("%s: creating thread for deferred free failed\n",
 		       __func__);
 		return PTR_RET(heap->task);
 	}
+	sched_setscheduler(heap->task, SCHED_IDLE, &param);
 	return 0;
 }