power_supply: bq2415x_charger: Use power_supply_*() API for accessing function attrs

Replace direct calls to power supply function attributes with wrappers.
Wrappers provide safe access in case of unregistering the power
supply (e.g. by removing the driver). Replace:
 - get_property -> power_supply_get_property
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/bq2415x_charger.c

@@ -809,7 +809,8 @@ static int bq2415x_notifier_call(struct notifier_block *nb,
 
 	dev_dbg(bq->dev, "notifier call was called\n");
 
-	ret = psy->get_property(psy, POWER_SUPPLY_PROP_CURRENT_MAX, &prop);
+	ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_CURRENT_MAX,
+			&prop);
 	if (ret != 0)
 		return NOTIFY_OK;