Merge branch 'mptcp-a-bunch-of-assorted-fixes'

Paolo Abeni says:

====================
mptcp: a bunch of assorted fixes

This series pulls a few fixes for the MPTCP datapath.
Most issues addressed here has been recently introduced
with the recent reworks, with the notable exception of
the first patch, which addresses an issue present since
the early days
====================

Link: https://lore.kernel.org/r/cover.1608114076.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>