leds: lm355x: Drop surplus include

This driver includes <linux/gpio.h> but does not use
any symbols from that file, so drop the include.

Cc: G.Shark Jeong <gshark.jeong@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

drivers/leds/leds-lm355x.c

@@ -7,7 +7,6 @@
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
-#include <linux/gpio.h>
 #include <linux/leds.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>