Merge branch 'act_csum-sctp'

Davide Caratti says:

====================
net/sched: act_csum: add support for SCTP checksum

This series extends current act_csum functionality to allow computation of
SCTP checksums. Patch 1 ensures LIBCRC32C will be selected if NET_ACT_CSUM
is selected. Patch 2 extends act_csum to handle IPPROTO_SCTP protocol in
IPv4/IPv6 header, and eventually compute the CRC32c value.

v2:
- style fix in tc_csum.h
- avoid nested if statement in act_csum.c
====================

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