team: allow to specify one option instance to be send to userspace

No need to walk through option instance list and look for ->changed ==
true when called knows exactly what one option instance changed.

Also use lists to pass option instances needed to be present in netlink
message.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>