platform: cznic: use new GPIO line value setter callbacks

platform: cznic: 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: Marek Behún <kabel@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/20250610-gpiochip-set-rv-platform-cznic-v1-1-30afd2444756@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>