power_supply: charger-manager: Add parent for power supply

The 'parent' argument passed to power_supply_register() is now used to
postpone callbacks to the driver until the driver's probe end.

Pass current device from charger-manager to utilize that. This will move
created power supply from virtual to platform devices.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>