pinctrl: mtk: Fix mt8365 Kconfig dependency

This SoC needs to select PINCTRL_MTK or we can end up in
kernel compiles that miss some symbols.

Cc: Fabien Parent <fparent@baylibre.com>
Reported-by: kernel test robot <lkp@intel.com>
Fixes: e94d8b6f ("pinctrl: mediatek: add support for mt8365 SoC")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>