ASoC: Intel: sst: remove unused ‘ret_val’

In sst_media_close(), 'ret_val' is initialized and assigned as return value
of stream ops close but never used. So remove it.

ound/soc/intel/atom/sst-mfld-platform-pcm.c: In function ‘sst_media_close’:
sound/soc/intel/atom/sst-mfld-platform-pcm.c:360:6: warning: variable ‘ret_val’ set but not used [-Wunused-but-set-variable]
  int ret_val = 0, str_id;
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/atom/sst-mfld-platform-pcm.c

@@ -357,14 +357,14 @@ static void sst_media_close(struct snd_pcm_substream *substream,
 		struct snd_soc_dai *dai)
 {
 	struct sst_runtime_stream *stream;
-	int ret_val = 0, str_id;
+	int str_id;
 
 	stream = substream->runtime->private_data;
 	power_down_sst(stream);
 
 	str_id = stream->stream_info.str_id;
 	if (str_id)
-		ret_val = stream->ops->close(sst->dev, str_id);
+		stream->ops->close(sst->dev, str_id);
 	module_put(sst->dev->driver->owner);
 	kfree(stream);
 }