gpio: Fix uninitialized variable bit in adp5588_irq_handler

The variable 'bit' is uninitialized in the first iteration of for
loop. Fix it.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/gpio/gpio-adp5588.c b/drivers/gpio/gpio-adp5588.c
index 9ad1703..ae5d7f1 100644
--- a/drivers/gpio/gpio-adp5588.c
+++ b/drivers/gpio/gpio-adp5588.c
@@ -252,7 +252,7 @@
 		if (ret < 0)
 			memset(dev->irq_stat, 0, ARRAY_SIZE(dev->irq_stat));
 
-		for (bank = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);
+		for (bank = 0, bit = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);
 			bank++, bit = 0) {
 			pending = dev->irq_stat[bank] & dev->irq_mask[bank];