decode-event: Add SCTP event

Almost empty now, because the only definition is packet
too small.

src/decode-events.h

@@ -176,6 +176,9 @@ enum {
     STREAM_REASSEMBLY_SEGMENT_BEFORE_BASE_SEQ,
     STREAM_REASSEMBLY_NO_SEGMENT,
 
+    /* SCTP EVENTS */
+    SCTP_PKT_TOO_SMALL,              /**< sctp packet smaller than minimum size */
+
     /* should always be last! */
     DECODE_EVENT_MAX,
 };