pinctrl/at91: using for_each_set_bit to simplify the code

Using for_each_set_bit() to simplify the code.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-at91.c

@@ -1219,10 +1219,8 @@ static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
 			continue;
 		}
 
-		n = find_first_bit(&isr, BITS_PER_LONG);
-		while (n < BITS_PER_LONG) {
+		for_each_set_bit(n, &isr, BITS_PER_LONG) {
 			generic_handle_irq(irq_find_mapping(at91_gpio->domain, n));
-			n = find_next_bit(&isr, BITS_PER_LONG, n + 1);
 		}
 	}
 	chained_irq_exit(chip, desc);