Merge branch 'pernet_ops-conversions-part-2'

Kirill Tkhai says:

====================
Converting pernet_operations (part #2)

This patchset continues to review and to convert pernet_operations
to async. There are mostly ipv6, also some regular used netfilter
pernet_operations are involved. One more converted is cfg80211_pernet_ops.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>