sctp: remove prsctp_param from sctp_chunk

Now sctp uses chunk->prsctp_param to save the prsctp param for all the
prsctp polices, we didn't need to introduce prsctp_param to sctp_chunk.
We can just use chunk->sinfo.sinfo_timetolive for RTX and BUF polices,
and reuse msg->expires_at for TTL policy, as the prsctp polices and old
expires policy are mutual exclusive.

This patch is to remove prsctp_param from sctp_chunk, and reuse msg's
expires_at for TTL and chunk's sinfo.sinfo_timetolive for RTX and BUF
polices.

Note that sctp can't use chunk's sinfo.sinfo_timetolive for TTL policy,
as it needs a u64 variables to save the expires_at time.

This one also fixes the "netperf-Throughput_Mbps -37.2% regression"
issue.

Fixes: a6c2f792873a ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 72e54a4..e084f35 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -383,7 +383,7 @@
 
 	list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
 		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
-		    chk->prsctp_param <= sinfo->sinfo_timetolive)
+		    chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)
 			continue;
 
 		list_del_init(&chk->transmitted_list);
@@ -418,7 +418,7 @@
 
 	list_for_each_entry_safe(chk, temp, queue, list) {
 		if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
-		    chk->prsctp_param <= sinfo->sinfo_timetolive)
+		    chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)
 			continue;
 
 		list_del_init(&chk->list);