pinctrl: mediatek: make MediaTek MT6765 pinctrl ready for buiding loadable module

This patch make pinctrl-mt6765 ready for building as loadable module.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Light Hsieh <light.hsieh@mediatek.com>
Link: https://lore.kernel.org/r/42100afe6f97d28447c153bea6b54ea556cf95ca.1586289920.git.sean.wang@mediatek.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>