MINOR: quic: Store post handshake frame in ->pktns.tx.frms MT_LIST

We want to treat all the frames to be built the same way as frames
built during handshake (CRYPTO frames). So, let't store them at the same
place which is an MT_LIST.
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index f520a9b..90761c9 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -2224,37 +2224,39 @@
  * a HANDSHAKE_DONE frame.
  * Return 1 if succeeded, 0 if not.
  */
-static int quic_build_post_handshake_frames(struct quic_conn *conn)
+static int quic_build_post_handshake_frames(struct quic_conn *qc)
 {
 	int i;
+	struct quic_enc_level *qel;
 	struct quic_frame *frm;
 
+	qel = &qc->els[QUIC_TLS_ENC_LEVEL_APP];
 	/* Only servers must send a HANDSHAKE_DONE frame. */
-	if (!objt_server(conn->conn->target)) {
+	if (!objt_server(qc->conn->target)) {
 		frm = pool_alloc(pool_head_quic_frame);
 		if (!frm)
 			return 0;
 
 		frm->type = QUIC_FT_HANDSHAKE_DONE;
-		LIST_APPEND(&conn->tx.frms_to_send, &frm->list);
+		MT_LIST_APPEND(&qel->pktns->tx.frms, &frm->mt_list);
 	}
 
-	for (i = 1; i < conn->tx.params.active_connection_id_limit; i++) {
+	for (i = 1; i < qc->tx.params.active_connection_id_limit; i++) {
 		struct quic_connection_id *cid;
 
 		frm = pool_alloc(pool_head_quic_frame);
-		cid = new_quic_cid(&conn->cids, i);
+		cid = new_quic_cid(&qc->cids, i);
 		if (!frm || !cid)
 			goto err;
 
 		quic_connection_id_to_frm_cpy(frm, cid);
-		LIST_APPEND(&conn->tx.frms_to_send, &frm->list);
+		MT_LIST_APPEND(&qel->pktns->tx.frms, &frm->mt_list);
 	}
 
     return 1;
 
  err:
-	free_quic_conn_cids(conn);
+	free_quic_conn_cids(qc);
 	return 0;
 }