power: supply: core: get rid of of_node

This removes .of_node from 'struct power_supply', since there
is already a copy in .dev.of_node and there is no need to have
two copies.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20250225-psy-core-convert-to-fwnode-v1-1-d5e4369936bb@collabora.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>