pinctrl: em: drop the wrapper around pinctrl_gpio_request()

pinctrl_gpio_request() now has the same signature as the wrapper around
it so we can drop them.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>