Merge branch 'rtnetlink-rtnl_lock'

Jakub Kicinski says:

====================
rtnetlink: move rtnl_lock handling out of af_netlink

With the changes done in commit 5b4b62a1 ("rtnetlink: make
the "split" NLM_DONE handling generic") we can also move the
rtnl locking out of af_netlink.
====================

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