MFC r218710:
Fix a regression introduced in r215906. The change made in r215906
caused link re-negotiation whenever application joins or leaves a
multicast group. If driver is running, it would have established a
link so there is no need to start re-negotiation. The re-negotiation
broke established link which in turn stopped multicast application
working while re-negotiation is in progress.
PR: kern/154667
git-svn-id: svn://svn.freebsd.org/base/stable/8@218962
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