sctp: fix the comment of sctp_sf_violation_paramlen()

Update the comment about sctp_sf_violation_paramlen() to be
more precise.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/sm_statefuns.c

@@ -4343,8 +4343,9 @@ static sctp_disposition_t sctp_sf_violation_chunklen(
 
 /*
  * Handle a protocol violation when the parameter length is invalid.
- * "Invalid" length is identified as smaller than the minimal length a
- * given parameter can be.
+ * If the length is smaller than the minimum length of a given parameter,
+ * or accumulated length in multi parameters exceeds the end of the chunk,
+ * the length is considered as invalid.
  */
 static sctp_disposition_t sctp_sf_violation_paramlen(
 				     const struct sctp_endpoint *ep,