SCTP: address coverity-scan warnings

Change-Id: Iba7c398a398e24b96eb536bbcefa841bd153a205
Signed-off-by: Marco Varlese <marco.varlese@suse.com>
diff --git a/src/vnet/sctp/sctp_output.c b/src/vnet/sctp/sctp_output.c
index 3ec54dc..ef5d3b7 100644
--- a/src/vnet/sctp/sctp_output.c
+++ b/src/vnet/sctp/sctp_output.c
@@ -680,8 +680,7 @@
   if (PREDICT_TRUE (ip6_addr != NULL))
     {
       sctp_ipv6_addr_param_t *ipv6_addr =
-	(sctp_ipv6_addr_param_t *) init_ack_chunk +
-	sizeof (sctp_init_chunk_t) + pointer_offset;
+	(sctp_ipv6_addr_param_t *) init_ack_chunk + pointer_offset;
 
       ipv6_addr->param_hdr.type =
 	clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);