greybus: power_supply: fix error path at supplies setup

If something goes wrong at setup time for the supplies, we need to
release all the resources allocated already.

Call the supplies release function which will handle the correct
teardown of the supplies.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Reported-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>