power: supply: Fix indentation and some other warnings

These were mentioned by checkpatch:
	Errors:
		(1) code indent should use tabs where possible
		(2) switch and case should be at the same indent
	Warnings:
		(1) Missing a blank line after declarations
Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/power_supply_core.c

@@ -1255,6 +1255,7 @@ EXPORT_SYMBOL_GPL(power_supply_powers);
 static void power_supply_dev_release(struct device *dev)
 {
 	struct power_supply *psy = to_power_supply(dev);
+
 	dev_dbg(dev, "%s\n", __func__);
 	kfree(psy);
 }