leds: leds-ns2: replace strict_strtoul() with kstrtoul()

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-ns2.c

@@ -149,7 +149,7 @@ static ssize_t ns2_led_sata_store(struct device *dev,
 	unsigned long enable;
 	enum ns2_led_modes mode;
 
-	ret = strict_strtoul(buff, 10, &enable);
+	ret = kstrtoul(buff, 10, &enable);
 	if (ret < 0)
 		return ret;