Merge branch 'mptcp-introduce-msk-diag-interface'

Paolo Abeni says:

====================
mptcp: introduce msk diag interface

This series implements the diag interface for the MPTCP sockets.

Since the MPTCP protocol value can't be represented with the
current diag uAPI, the first patch introduces an extended attribute
allowing user-space to specify lager protocol values.

The token APIs are then extended to allow traversing the
whole token container.

Patch 3 carries the actual diag interface implementation, and
later patch bring-in some functional self-tests.
====================

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