pinctrl: mediatek: fix dual-edge code defect

[ Upstream commit 5edf673d ]

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.

Cc: stable@vger.kernel.org
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: Sasha Levin <sasha.levin@oracle.com>

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

@@ -1030,9 +1030,10 @@ static void mtk_eint_irq_handler(unsigned irq, 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;