SCTP: Fix to handle invalid parameter length correctly

If an INIT with invalid parameter length look like this:
Parameter Type : 1
Parameter Length: 800
and not contain any payload, SCTP will ignore this  parameter and send
back a INIT-ACK.
This patch is fix to handle this invalid parameter length correctly.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>