team: call netdev_change_features out of team lock

Commit f6988cb6 ("team: don't call netdev_change_features under
team->lock") fixed the issue calling netdev_change_features under
team->lock for team_compute_features.

But there are still two places where it calls netdev_change_features
under team->lock, team_port_add and team_port_del. It may cause a
dead lock when the slave port with LRO enabled is added.

This patch is to fix this dead lock by moving netdev_change_features
out of team_port_add and team_port_del, and call it after unlocking
the team lock.

Reported-by: Patrick Talbert <ptalbert@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>