power_supply: Use wrappers to avoid races when registering power supply

Use wrappers over get_property() and set_property() internally in power
supply and for sysfs interface. The wrappers provide safe access if
power supply is not yet registered or t is being destroyed.

In case of syfs the theoretical race could happen between ending of
driver's probe and parallel sysfs access:
some_driver_probe() userspace
==================================== ===========================
drv->psy = power_supply_register()
device_add()
sysfs entries are created
atomic_inc(&psy->use_cnt);
store on sysfs attributes
drv->set_property()
dereference of drv->psy
drv->psy = returned psy;

For leds the race could happen between power supply being destroyed and
ongoing power_supply_changed_work().

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/power_supply_leds.c

···
 	unsigned long delay_on = 0;
 	unsigned long delay_off = 0;
 
-	if (psy->desc->get_property(psy, POWER_SUPPLY_PROP_STATUS, &status))
+	if (power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS, &status))
 		return;
 
 	dev_dbg(&psy->dev, "%s %d\n", __func__, status.intval);
···
 {
 	union power_supply_propval online;
 
-	if (psy->desc->get_property(psy, POWER_SUPPLY_PROP_ONLINE, &online))
+	if (power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE, &online))
 		return;
 
 	dev_dbg(&psy->dev, "%s %d\n", __func__, online.intval);

drivers/power/power_supply_sysfs.c

···
 
 	value.intval = long_val;
 
-	ret = psy->desc->set_property(psy, off, &value);
+	ret = power_supply_set_property(psy, off, &value);
 	if (ret < 0)
 		return ret;