ASoC: sst_platform: unregister sst card when being closed

Signed-off-by: Lu Guanqun <guanqun.lu@intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/mid-x86/sst_platform.c b/sound/soc/mid-x86/sst_platform.c
index 848ad3c..9ba9414 100644
--- a/sound/soc/mid-x86/sst_platform.c
+++ b/sound/soc/mid-x86/sst_platform.c
@@ -271,6 +271,7 @@
 	str_id = stream->stream_info.str_id;
 	if (str_id)
 		ret_val = stream->sstdrv_ops->pcm_control->close(str_id);
+	unregister_sst_card(stream->sstdrv_ops);
 	kfree(stream->sstdrv_ops);
 	kfree(stream);
 	return ret_val;