pinctrl: mediatek: Fix trigger type setting follow for unexpected interrupt

pinctrl: mediatek: Fix trigger type setting follow for unexpected interrupt

When flipping the polarity will be generated interrupt under certain
circumstances, but GPIO external signal has not changed.
Then, mask the interrupt before polarity setting, and clear the
unexpected interrupt after trigger type setting completed.

Remove mtk_eint_flip_edge: because mtk_eint_unmask already calls it.

Signed-off-by: Hailong Fan <hailong.fan@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Link: https://lore.kernel.org/r/20210125041753.2214-1-hailong.fan@mediatek.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>