pinctrl: nomadik: 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-nomadik.c

@@ -8,6 +8,7 @@
  * Copyright (C) 2011-2013 Linus Walleij <linus.walleij@linaro.org>
  */
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -917,7 +918,6 @@ static void nmk_gpio_dbg_show_one(struct seq_file *s,
 	struct pinctrl_dev *pctldev, struct gpio_chip *chip,
 	unsigned offset, unsigned gpio)
 {
-	const char *label = gpiochip_is_requested(chip, offset);
 	struct nmk_gpio_chip *nmk_chip = gpiochip_get_data(chip);
 	int mode;
 	bool is_out;
@@ -934,6 +934,10 @@ static void nmk_gpio_dbg_show_one(struct seq_file *s,
 		[NMK_GPIO_ALT_C+4]	= "altC4",
 	};
 
+	char *label = gpiochip_dup_line_label(chip, offset);
+	if (IS_ERR(label))
+		return;
+
 	clk_enable(nmk_chip->clk);
 	is_out = !!(readl(nmk_chip->addr + NMK_GPIO_DIR) & BIT(offset));
 	pull = !(readl(nmk_chip->addr + NMK_GPIO_PDIS) & BIT(offset));