pinctrl: mediatek: fix dual-edge code defect

commit 5edf673d upstream.

When a dual-edge irq is triggered, an incorrect irq will be reported on
condition that the external signal is not stable and this incorrect irq
has been registered.
Correct the register offset.
Signed-off-by: Hongkun Cao <hongkun.cao@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pinctrl/mediatek/pinctrl-mtk-common.c

@@ -1256,9 +1256,10 @@ static void mtk_eint_irq_handler(struct irq_desc *desc)
 	const struct mtk_desc_pin *pin;
 
 	chained_irq_enter(chip, desc);
-	for (eint_num = 0; eint_num < pctl->devdata->ap_num; eint_num += 32) {
+	for (eint_num = 0;
+	     eint_num < pctl->devdata->ap_num;
+	     eint_num += 32, reg += 4) {
 		status = readl(reg);
-		reg += 4;
 		while (status) {
 			offset = __ffs(status);
 			index = eint_num + offset;