pinctrl: cirrus: lochnagar: use new GPIO line value setter callbacks

struct gpio_chip now has callbacks for setting line values that return
an integer, allowing to indicate failures. Convert the driver to using
them.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/20250612-gpiochip-set-rv-pinctrl-cirrus-v1-1-2d45c1f92557@linaro.org


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>