ASoC: mediatek: mt8192: use asoc_substream_to_rtd()

Uses asoc_substream_to_rtd() helper.
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20210203032201.2882158-3-tzungbi@google.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/mt8192/mt8192-afe-pcm.c

@@ -42,7 +42,7 @@ static const struct snd_pcm_hardware mt8192_afe_hardware = {
 static int mt8192_memif_fs(struct snd_pcm_substream *substream,
 			   unsigned int rate)
 {
-	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_component *component =
 		snd_soc_rtdcom_lookup(rtd, AFE_PCM_NAME);
 	struct mtk_base_afe *afe = snd_soc_component_get_drvdata(component);
@@ -59,7 +59,7 @@ static int mt8192_get_dai_fs(struct mtk_base_afe *afe,
 
 static int mt8192_irq_fs(struct snd_pcm_substream *substream, unsigned int rate)
 {
-	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_component *component =
 		snd_soc_rtdcom_lookup(rtd, AFE_PCM_NAME);
 	struct mtk_base_afe *afe = snd_soc_component_get_drvdata(component);