power: supply: Fix power_supply_am_i_supplied to return -ENODEV when apropriate

Commit 2848e039 ("power: supply: Make power_supply_am_i_supplied return
-ENODEV if there are no suppliers") was supposed to make
power_supply_am_i_supplied() return -ENODEV when there are no supplies
which supply the supply passed to it.

But instead it will only return -ENODEV when there are no supplies at
all as data->count++; is incremented on every call of the iterator, rather
then only when __power_supply_is_supplied_by returns true. This commit
fixes this.

Fixes: 2848e039 ("power: supply: Make power_supply_am_i_supplied ...")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

drivers/power/supply/power_supply_core.c

@@ -314,11 +314,12 @@ static int __power_supply_am_i_supplied(struct device *dev, void *_data)
 	struct power_supply *epsy = dev_get_drvdata(dev);
 	struct psy_am_i_supplied_data *data = _data;
 
-	data->count++;
-	if (__power_supply_is_supplied_by(epsy, data->psy))
+	if (__power_supply_is_supplied_by(epsy, data->psy)) {
+		data->count++;
 		if (!epsy->desc->get_property(epsy, POWER_SUPPLY_PROP_ONLINE,
 					&ret))
 			return ret.intval;
+	}
 
 	return 0;
 }