gpio: mockup: don't access internal GPIOLIB structures

gpio: mockup: don't access internal GPIOLIB structures

Don't include gpiolib.h. Track the request status of lines locally
instead. In order to retrieve the device name use the fact that
gpio-mockup supports only a single GPIO device per platform device and
call device_find_any_child().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>