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

Paolo Abeni says:

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

This series bundle a few MPTCP fixes for the current net tree.
They have been detected via syzkaller and packetdrill

Patch 1 fixes a slow close for orphaned sockets

Patch 2 fixes another hangup at close time, when no
data was actually transmitted before close

Patch 3 fixes a memory leak with unusual sockopts

Patch 4 fixes stray wake-ups on listener sockets
====================

Link: https://lore.kernel.org/r/cover.1613755058.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>