Merge branch 'sctp_diag-fixes'

Phil Sutter says:

====================
sctp_diag: A bunch of fixes for upcoming 'ss' support

The following series contains a number of fixes necessary to make my yet
unpublished 'ss' support patch functional.

Changes since v1:
- Fixed patch 2/3
- Rebased whole series onto current net-next/master

Changes since v2:
- Improved description of patch 2/3
====================

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