This reverts commit 12dfd78e.

This can be reverted as shutdown and cookie_ack chunk are using the
same asoc since commit 35b4f244 ("sctp: do asoc update earlier
in sctp_sf_do_dupcook_a").
Reported-by: NJere Leppänen <jere.leppanen@nokia.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>