leds: leds-lp5523: 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strict_strtoul() is obsolete.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-lp5523.c

@@ -710,7 +710,7 @@ static ssize_t store_current(struct device *dev,
 	ssize_t ret;
 	unsigned long curr;
 
-	if (strict_strtoul(buf, 0, &curr))
+	if (kstrtoul(buf, 0, &curr))
 		return -EINVAL;
 
 	if (curr > led->max_current)