Merge branch 'sctp-sender-side-stream-reconf-ssn-reset-request-chunk'

Xin Long says:

====================
sctp: add sender-side procedures for stream reconf ssn reset request chunk

Patch 6/6 is to implement sender-side procedures for the Outgoing
and Incoming SSN Reset Request Parameter described in rfc6525
section 5.1.2 and 5.1.3

Patches 1-5/6 are ahead of it to define some apis and asoc members
for it.

Note that with this patchset, asoc->reconf_enable has no chance yet to
be set, until the patch "sctp: add get and set sockopt for reconf_enable"
is applied in the future. As we can not just enable it when sctp is not
capable of processing reconf chunk yet.

v1->v2:
  - put these into a smaller group.
  - rename some temporary variables in the codes.
  - rename the titles of the commits and improve some changelogs.
v2->v3:
  - re-split the patchset and make sure it has no dead codes for review.
v3->v4:
  - move sctp_make_reconf() into patch 1/6 to avoid kbuild warning.
  - drop unused struct sctp_strreset_req.
====================

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