leds: trigger: gpio: Use sysfs_emit() to instead of s*printf()

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20231103195310.948327-3-andriy.shevchenko@linux.intel.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/trigger/ledtrig-gpio.c

@@ -46,7 +46,7 @@ static ssize_t gpio_trig_brightness_show(struct device *dev,
 {
 	struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
 
-	return sprintf(buf, "%u\n", gpio_data->desired_brightness);
+	return sysfs_emit(buf, "%u\n", gpio_data->desired_brightness);
 }
 
 static ssize_t gpio_trig_brightness_store(struct device *dev,