Merge branch 'mptcp-Fix-for-32-bit-DATA_FIN'

Mat Martineau says:

====================
mptcp: Fix for 32-bit DATA_FIN

The main fix is contained in patch 2, and that commit message explains
the issue with not properly converting truncated DATA_FIN sequence
numbers sent by the peer.

With patch 2 adding an unlocked read of msk->ack_seq, patch 1 cleans up
access to that data with READ_ONCE/WRITE_ONCE.

This does introduce two merge conflicts with net-next, but both have
straightforward resolution. Patch 1 modifies a line that got removed in
net-next so the modification can be dropped when merging. Patch 2 will
require a trivial conflict resolution for a modified function
declaration.
====================

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