net: devlink: fix return statement in devlink_port_new_notify()

Return directly without intermediate value store at the end of
devlink_port_new_notify() function.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>