gpio/ml-ioh: fix off-by-one for displaying variable i in dev_err

with the "for (; i != 0; i--)" sytax, i-- will be executed after the iteration.
thus dev_err shows wrong i value.
Switch to "while(--i >= 0)" which is better in readability.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

drivers/gpio/gpio-ml-ioh.c

@@ -233,7 +233,7 @@ static int __devinit ioh_gpio_probe(struct pci_dev *pdev,
 	return 0;
 
 err_gpiochip_add:
-	for (; i != 0; i--) {
+	while (--i >= 0) {
 		chip--;
 		ret = gpiochip_remove(&chip->gpio);
 		if (ret)