leds: lgm: Fix up includes

This driver is including the legacy GPIO header <linux/gpio.h>
but the only thing it is using from that header is the wrong
define for GPIOF_DIR_OUT.

Fix it up by using GPIO_LINE_DIRECTION_OUT and including the
correct consumer and driver headers.

Cc: Amireddy Mallikarjuna reddy <mallikarjunax.reddy@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>