gpio: TODO: add an item to track the conversion to the new value setters

Add an item tracking the treewide conversion of GPIO drivers to using
the new line value setter callbacks in struct gpio_chip instead of the
old ones that don't allow drivers to signal failures to callers.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250321-gpio-todo-updates-v1-5-7b38f07110ee@linaro.org


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>