Merge branch 'sctp_csum'

Daniel Borkmann says:

====================
SCTP fix/updates

Please see patch 5 for the main description/motivation, the rest just
brings in the needed functionality for that. Although this is actually
a fix, I've based it against net-next as some additional work for
fixing it was needed.
====================

Acked-by: Neil Horman <[email protected]>
Acked-by: Vlad Yasevich <[email protected]>
Signed-off-by: David S. Miller <[email protected]>