pinctrl: sx150x: fix up headers

Include <linux/gpio/driver.h> rather than <linux/gpio.h>
Drop <linux/pinctrl/machine.h>.

Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>