gpio: TODO: remove task duplication

The removal of linux/gpio.h is already tracked by the item about
converting drivers to using the descriptor-based API. Remove the
duplicate.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250321-gpio-todo-updates-v1-2-7b38f07110ee@linaro.org


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