gpiolib: use v2 defines for line state change events

We should only use v2 defines for line state change events. They will get
tranlated to v1 if needed by gpio_v2_line_info_changed_to_v1().

This isn't really a functional change as they have the same values but
let's do it for consistency.

Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20241004-gpio-notify-in-kernel-events-v1-1-8ac29e1df4fe@linaro.org


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