Merge branch 'l2tp-misc-improvements'

James Chapman says:

====================
l2tp: misc improvements

This series makes several improvements to l2tp:

 * update documentation to be consistent with recent l2tp changes.
 * move l2tp_ip socket tables to per-net data.
 * fix handling of hash key collisions in l2tp_v3_session_get
 * implement and use get-next APIs for management and procfs/debugfs.
 * improve l2tp refcount helpers.
 * use per-cpu dev->tstats in l2tpeth devices.
 * fix a lockdep splat.
 * fix a race between l2tp_pre_exit_net and pppol2tp_release.
====================

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