Merge branch 'l2tp-drop-l2tp_session_find'

Guillaume Nault says:

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l2tp: drop l2tp_session_find()

l2tp_netlink is the last user of l2tp_session_find(), but that call is
useless. Let's remove it and drop l2tp_session_find() definitely.
====================

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