ASoC: stm32: fix a typo in stm32_adfsdm_probe()

Fix a typo, we should return PTR_ERR(priv->iio_cb) instead of
PTR_ERR(priv->iio_ch).

Fixes: 55da094824c4 ("ASoC: stm32: add DFSDM DAI support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_adfsdm.c

@@ -320,7 +320,7 @@ static int stm32_adfsdm_probe(struct platform_device *pdev)
 
 	priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, NULL, NULL);
 	if (IS_ERR(priv->iio_cb))
-		return PTR_ERR(priv->iio_ch);
+		return PTR_ERR(priv->iio_cb);
 
 	ret = devm_snd_soc_register_platform(&pdev->dev,
 					     &stm32_adfsdm_soc_platform);