switchdev: remove old switchdev_port_bridge_setlink

New attr-based bridge_setlink can recurse lower devs and recover on err, so
remove old wrapper (including ndo_dflt_switchdev_port_bridge_setlink).

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>