sctp: fix bogus if statement in sctp_auth_recv_cid()

There is an extra semi-colon here, so we always return 0 instead of
calling __sctp_auth_cid().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>