[SCTP]: Fix miss of report unrecognized HMAC Algorithm parameter

This patch fix miss of check for report unrecognized HMAC Algorithm
parameter.  When AUTH is disabled, goto fall through path to report
unrecognized parameter, else, just break

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>