pinctrl: imx: Check for memory allocation failure

If 'devm_kzalloc' fails, a NULL pointer will be dereferenced.
Return -ENOMEM instead, as done for the other memory allocation just a
few lines below.
BTW, change the 'devm_kzalloc' into a 'devm_kcalloc'.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/freescale/pinctrl-imx.c

@@ -581,9 +581,10 @@ static int imx_pinctrl_parse_functions(struct device_node *np,
 		dev_err(info->dev, "no groups defined in %s\n", np->full_name);
 		return -EINVAL;
 	}
-	func->group_names = devm_kzalloc(info->dev,
-					 func->num_group_names *
+	func->group_names = devm_kcalloc(info->dev, func->num_group_names,
 					 sizeof(char *), GFP_KERNEL);
+	if (!func->group_names)
+		return -ENOMEM;
 
 	for_each_child_of_node(np, child) {
 		func->group_names[i] = child->name;