Merge branch 'l2tp-tunnel-creation-fixes'

Guillaume Nault says:

====================
l2tp: tunnel creation fixes

L2TP tunnel creation is racy. We need to make sure that the tunnel
returned by l2tp_tunnel_create() isn't going to be freed while the
caller is using it. This is done in patch #1, by separating tunnel
creation from tunnel registration.

With the tunnel registration code in place, we can now check for
duplicate tunnels in a race-free way. This is done in patch #2, which
incidentally removes the last use of l2tp_tunnel_find().
====================

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