gpio: blzp1600: drop dependency on OF headers

gpio: blzp1600: drop dependency on OF headers

Use the generic boolean device property getter instead of the
OF-specific variant. This allows us to stop pulling in linux/of.h. While
at it: drop the of_irq.h inclusion as none of its symbols are used in
this driver.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Nikolaos Pasaloukos <nikolaos.pasaloukos@blaize.com>
Link: https://lore.kernel.org/r/20250408143629.125576-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>