power: supply: core: Add support for generic fwnodes to power_supply_get_battery_info()

Add support to power_supply_get_battery_info() to read the properties from
other fwnode types such as swnodes added by platform code on x86 devices.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>