gpio: bd71815: use new line value setter callbacks

gpio: bd71815: use new 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.

Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/20250310-gpiochip-set-conversion-v1-3-03798bb833eb@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>