ASoC: mediatek: mt2701: fix return value check in mt2701_afe_pcm_dev_probe()

In case of error, the function syscon_node_to_regmap() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().

Fixes: dfa3cbb8 ("ASoC: mediatek: modify MT2701 AFE driver to adapt mfd device")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/mt2701/mt2701-afe-pcm.c

@@ -1440,9 +1440,9 @@ static int mt2701_afe_pcm_dev_probe(struct platform_device *pdev)
 	}
 
 	afe->regmap = syscon_node_to_regmap(dev->parent->of_node);
-	if (!afe->regmap) {
+	if (IS_ERR(afe->regmap)) {
 		dev_err(dev, "could not get regmap from parent\n");
-		return -ENODEV;
+		return PTR_ERR(afe->regmap);
 	}
 
 	mutex_init(&afe->irq_alloc_lock);