of: property: fw_devlink: Add support for "power-supplies" binding

Add support for parsing power-supplies binding so that fw_devlink can
enforce the dependency.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Cc: Sebastian Reichel <sre@kernel.org>
Link: https://lore.kernel.org/r/20240417200738.1370896-1-saravanak@google.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>