pinctrl: st: fix return value check

In case of error, the function pinctrl_register() returns
NULL not ERR_PTR(). The IS_ERR() test in the return value
check should be replaced with NULL test.
The function syscon_regmap_lookup_by_phandle() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/pinctrl/pinctrl-st.c

@@ -1299,9 +1299,9 @@ static int st_pctl_probe_dt(struct platform_device *pdev,
 		return -ENOMEM;
 
 	info->regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
-	if (!info->regmap) {
+	if (IS_ERR(info->regmap)) {
 		dev_err(info->dev, "No syscfg phandle specified\n");
-		return -ENOMEM;
+		return PTR_ERR(info->regmap);
 	}
 	info->data = of_match_node(st_pctl_of_match, np)->data;
 
@@ -1376,9 +1376,9 @@ static int st_pctl_probe(struct platform_device *pdev)
 	pctl_desc->name		= dev_name(&pdev->dev);
 
 	info->pctl = pinctrl_register(pctl_desc, &pdev->dev, info);
-	if (IS_ERR(info->pctl)) {
+	if (!info->pctl) {
 		dev_err(&pdev->dev, "Failed pinctrl registration\n");
-		return PTR_ERR(info->pctl);
+		return -EINVAL;
 	}
 
 	for (i = 0; i < info->nbanks; i++)