pinctrl: qcom: ssbi: convert null test to IS_ERR test

Since commit 323de9e ("pinctrl: make pinctrl_register() return proper
error code"), pinctrl_register returns an error code rather than NULL on
failure.  Update some drivers that were introduced more recently.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression e,e1,e2;
@@

e = pinctrl_register(...)
... when != e = e1
if (
-   e == NULL
+   IS_ERR(e)
   ) {
     ...
     return
-      e2
+      PTR_ERR(e)
     ;
     }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c

@@ -723,9 +723,9 @@ static int pm8xxx_gpio_probe(struct platform_device *pdev)
 #endif
 
 	pctrl->pctrl = pinctrl_register(&pctrl->desc, &pdev->dev, pctrl);
-	if (!pctrl->pctrl) {
+	if (IS_ERR(pctrl->pctrl)) {
 		dev_err(&pdev->dev, "couldn't register pm8xxx gpio driver\n");
-		return -ENODEV;
+		return PTR_ERR(pctrl->pctrl);
 	}
 
 	pctrl->chip = pm8xxx_gpio_template;

drivers/pinctrl/qcom/pinctrl-ssbi-mpp.c

@@ -814,9 +814,9 @@ static int pm8xxx_mpp_probe(struct platform_device *pdev)
 #endif
 
 	pctrl->pctrl = pinctrl_register(&pctrl->desc, &pdev->dev, pctrl);
-	if (!pctrl->pctrl) {
+	if (IS_ERR(pctrl->pctrl)) {
 		dev_err(&pdev->dev, "couldn't register pm8xxx mpp driver\n");
-		return -ENODEV;
+		return PTR_ERR(pctrl->pctrl);
 	}
 
 	pctrl->chip = pm8xxx_mpp_template;