Merge branch 'sctp-dup-stream-reconf-events'

Xin Long says:

====================
sctp: add proper process for duplicated stream reconf requests

Now sctp stream reconf will process a request again even if it's seqno
is less than asoc->strreset_inseq. It may cause a replay attack.

This patchset is to avoid it by add proper process for all duplicated
stream reconf requests.
====================

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