mtd: rawnand: ingenic: move the GPIO quirk to gpiolib-of.c

We have a special place for OF polarity quirks in gpiolib-of.c. Let's
move this over there so that it doesn't pollute the driver.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Andy Shevchenko <andy@kernel.org>