l2tp: put tunnel socket release on a workqueue

To allow l2tp_tunnel_delete to be called from an atomic context, place the
tunnel socket release calls on a workqueue for asynchronous execution.

Tunnel memory is eventually freed in the tunnel socket destructor.

Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/l2tp/l2tp_core.c
Simple merge

diff --cc net/l2tp/l2tp_core.h
Simple merge