gpio: sch: Include the right header

This is a GPIO driver, include only <linux/gpio/driver.h>.

Cc: Denis Turischev <denis.turischev@compulab.co.il>
Cc: Daniel Krueger <daniel.krueger@systec-electronic.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>