gpio: crystalcove: Use for_each_set_bit() in IRQ handler

This simplifies and standardizes the AB IRQ handler by using
the for_each_set_bit() library function.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

drivers/gpio/gpio-crystalcove.c

@@ -279,8 +279,8 @@ static struct irq_chip crystalcove_irqchip = {
 static irqreturn_t crystalcove_gpio_irq_handler(int irq, void *data)
 {
 	struct crystalcove_gpio *cg = data;
+	unsigned long pending;
 	unsigned int p0, p1;
-	int pending;
 	int gpio;
 	unsigned int virq;
 
@@ -293,12 +293,10 @@ static irqreturn_t crystalcove_gpio_irq_handler(int irq, void *data)
 
 	pending = p0 | p1 << 8;
 
-	for (gpio = 0; gpio < CRYSTALCOVE_GPIO_NUM; gpio++) {
-		if (pending & BIT(gpio)) {
+	for_each_set_bit(gpio, &pending, CRYSTALCOVE_GPIO_NUM) {
 		virq = irq_find_mapping(cg->chip.irq.domain, gpio);
 		handle_nested_irq(virq);
 	}
-	}
 
 	return IRQ_HANDLED;
 }