ASoC: hdac_hdmi: Fix possible memory leak in hw_params

It's possible for hw_params to be called two times. So add NULL
check to prevent memory leak.
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/hdac_hdmi.c

@@ -405,9 +405,13 @@ static int hdac_hdmi_set_hw_params(struct snd_pcm_substream *substream,
 		return -ENODEV;
 	}
 
-	dd = kzalloc(sizeof(*dd), GFP_KERNEL);
-	if (!dd)
-		return -ENOMEM;
+	dd = snd_soc_dai_get_dma_data(dai, substream);
+	if (!dd) {
+		dd = kzalloc(sizeof(*dd), GFP_KERNEL);
+		if (!dd)
+			return -ENOMEM;
+	}
+
 	dd->format = snd_hdac_calc_stream_format(params_rate(hparams),
 			params_channels(hparams), params_format(hparams),
 			24, 0);
@@ -433,9 +437,11 @@ static int hdac_hdmi_playback_cleanup(struct snd_pcm_substream *substream,
 				AC_VERB_SET_STREAM_FORMAT, 0);
 
 	dd = (struct hdac_ext_dma_params *)snd_soc_dai_get_dma_data(dai, substream);
-	snd_soc_dai_set_dma_data(dai, substream, NULL);
 
-	kfree(dd);
+	if (dd) {
+		snd_soc_dai_set_dma_data(dai, substream, NULL);
+		kfree(dd);
+	}
 
 	return 0;
 }