bq27x00: Return -ENODEV for properties if the battery is not present

This patch changes get_property callback of the bq27x00 battery to return
-ENODEV for properties other then the PROP_PRESENT if the battery is not
present.
The power subsystem core expects a driver to behave that way.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>

drivers/power/bq27x00_battery.c

@@ -252,16 +252,21 @@ static int bq27x00_battery_get_property(struct power_supply *psy,
 {
 	int ret = 0;
 	struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
+	int voltage = bq27x00_battery_voltage(di);
+
+	if (psp != POWER_SUPPLY_PROP_PRESENT && voltage <= 0)
+		return -ENODEV;
 
 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
 		ret = bq27x00_battery_status(di, val);
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = voltage;
+		break;
 	case POWER_SUPPLY_PROP_PRESENT:
-		val->intval = bq27x00_battery_voltage(di);
 		if (psp == POWER_SUPPLY_PROP_PRESENT)
-			val->intval = val->intval <= 0 ? 0 : 1;
+			val->intval = voltage <= 0 ? 0 : 1;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 		val->intval = bq27x00_battery_current(di);