pinctrl: abx500: use gpiochip_dup_line_label()

Use the new gpiochip_dup_line_label() helper to safely retrieve the
descriptor label.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/nomadik/pinctrl-abx500.c

@@ -6,7 +6,9 @@
  *
  * Driver allows to use AxB5xx unused pins to be used as GPIO
  */
+
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/gpio/driver.h>
 #include <linux/init.h>
@@ -453,12 +455,11 @@ static void abx500_gpio_dbg_show_one(struct seq_file *s,
 				     unsigned offset, unsigned gpio)
 {
 	struct abx500_pinctrl *pct = pinctrl_dev_get_drvdata(pctldev);
-	const char *label = gpiochip_is_requested(chip, offset - 1);
 	u8 gpio_offset = offset - 1;
 	int mode = -1;
 	bool is_out;
 	bool pd;
-	int ret;
+	int ret = -ENOMEM;
 
 	const char *modes[] = {
 		[ABX500_DEFAULT]	= "default",
@@ -474,6 +475,10 @@ static void abx500_gpio_dbg_show_one(struct seq_file *s,
 		[ABX500_GPIO_PULL_UP]		= "pull up",
 	};
 
+	char *label __free(kfree) = gpiochip_dup_line_label(chip, offset - 1);
+	if (IS_ERR(label))
+		goto out;
+
 	ret = abx500_gpio_get_bit(chip, AB8500_GPIO_DIR1_REG,
 			gpio_offset, &is_out);
 	if (ret < 0)