power: supply: core: rename power_supply_get_by_phandle to power_supply_get_by_reference

power: supply: core: rename power_supply_get_by_phandle to power_supply_get_by_reference

(devm_)power_supply_get_by_phandle now internally uses fwnode and are no
longer DT specific. Thus drop the ifdef check for CONFIG_OF and rename
to (devm_)power_supply_get_by_reference to avoid the DT terminology.

Reviewed-by: Hans de Goede <hansg@kernel.org>
Link: https://lore.kernel.org/r/20250430-psy-core-convert-to-fwnode-v2-5-f9643b958677@collabora.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>