ASoC: mediatek: mtk-btcvsd: Add checks for write and read of mtk_btcvsd_snd

As the mtk_btcvsd_snd_write and mtk_btcvsd_snd_read may return error,
it should be better to catch the exception.

Fixes: 4bd8597d ("ASoC: mediatek: add btcvsd driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://lore.kernel.org/r/20221116030750.40500-1-jiasheng@iscas.ac.cnSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/common/mtk-btcvsd.c

@@ -1038,11 +1038,9 @@ static int mtk_pcm_btcvsd_copy(struct snd_soc_component *component,
 	struct mtk_btcvsd_snd *bt = snd_soc_component_get_drvdata(component);
 
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-		mtk_btcvsd_snd_write(bt, buf, count);
+		return mtk_btcvsd_snd_write(bt, buf, count);
 	else
-		mtk_btcvsd_snd_read(bt, buf, count);
-
-	return 0;
+		return mtk_btcvsd_snd_read(bt, buf, count);
 }
 
 /* kcontrol */