regulator: mt6315: Fix checking return value of devm_regmap_init_spmi_ext

devm_regmap_init_spmi_ext() returns ERR_PTR() on error.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20210615132934.3453965-1-axel.lin@ingics.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/mt6315-regulator.c

@@ -223,8 +223,8 @@ static int mt6315_regulator_probe(struct spmi_device *pdev)
 	int i;
 
 	regmap = devm_regmap_init_spmi_ext(pdev, &mt6315_regmap_config);
-	if (!regmap)
-		return -ENODEV;
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
 
 	chip = devm_kzalloc(dev, sizeof(struct mt6315_chip), GFP_KERNEL);
 	if (!chip)