core: remove the active_low boolean argument from single-line requests

core: remove the active_low boolean argument from single-line requests

Remove the separate argument for setting the active-state to low in
helper functions doing the single GPIO line requests.

Introduce new variants of these helpers that allow to pass
a combination of all available flags to the request.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>