ASoC: Intel: Cancel hsw_notification_work before freeing the stream

I suppose there is a possibility that hsw_notification_work() may run after sst_hsw_stream_free() which can lead to a kernel crash since struct sst_hsw_stream is freed at that point and
stream = container_of(work, struct sst_hsw_stream, notify_work) is not valid when hsw_notification_work() is run.

---
Untested, I don't have at the moment Haswell to test this and Liam hasn't seen this patch yet so ack/tested-by from him might be good to have :-)

---
 sound/soc/intel/sst-haswell-ipc.c | 1 +
 1 file changed, 1 insertion(+)

index 6c0b4f247a86..5bcf5963a0ba 100644
@@ -1207,6 +1207,7 @@ int sst_hsw_stream_free(struct sst_hsw *hsw, struct sst_hsw_stream *stream)
 	trace_hsw_stream_free_req(stream, &stream->free_req);
 
 out:
+	cancel_work_sync(&stream->notify_work);
 	spin_lock_irqsave(&sst->spinlock, flags);
 	list_del(&stream->node);
 	kfree(stream);

1.9.2

Applied, thanks.