MINOR: conn-stream: Move some CS flags to the endpoint

Some CS flags, only related to the endpoint, are moved into the endpoint
struct. More will probably moved later. Those ones are not critical. So it
is pretty safe to move them now and this will ease next changes.
diff --git a/src/mux_h1.c b/src/mux_h1.c
index afc09df..82470bc 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -728,10 +728,10 @@
 	h1s->cs = cs;
 
 	if (h1s->flags & H1S_F_NOT_FIRST)
-		cs->flags |= CS_FL_NOT_FIRST;
+		cs->endp->flags |= CS_EP_NOT_FIRST;
 
 	if (h1s->req.flags & H1_MF_UPG_WEBSOCKET)
-		cs->flags |= CS_FL_WEBSOCKET;
+		cs->endp->flags |= CS_EP_WEBSOCKET;
 
 	if (!stream_new(h1c->conn->owner, cs, input)) {
 		TRACE_DEVEL("leaving on stream creation failure", H1_EV_STRM_NEW|H1_EV_STRM_END|H1_EV_STRM_ERR, h1c->conn, h1s);
@@ -1880,11 +1880,11 @@
 	/* Here h1s->cs is always defined */
 	if (!(h1m->flags & H1_MF_CHNK) && (h1m->state == H1_MSG_DATA || (h1m->state == H1_MSG_TUNNEL))) {
 		TRACE_STATE("notify the mux can use splicing", H1_EV_RX_DATA|H1_EV_RX_BODY, h1c->conn, h1s);
-		h1s->cs->flags |= CS_FL_MAY_SPLICE;
+		h1s->cs->endp->flags |= CS_EP_MAY_SPLICE;
 	}
 	else {
 		TRACE_STATE("notify the mux can't use splicing anymore", H1_EV_RX_DATA|H1_EV_RX_BODY, h1c->conn, h1s);
-		h1s->cs->flags &= ~CS_FL_MAY_SPLICE;
+		h1s->cs->endp->flags &= ~CS_EP_MAY_SPLICE;
 	}
 
 	/* Set EOI on conn-stream in DONE state iff:
@@ -3454,9 +3454,9 @@
 
 	TRACE_ENTER(H1_EV_STRM_SHUT, h1c->conn, h1s, 0, (size_t[]){mode});
 
-	if (cs->flags & CS_FL_SHR)
+	if (cs->endp->flags & CS_EP_SHR)
 		goto end;
-	if (cs->flags & CS_FL_KILL_CONN) {
+	if (cs->endp->flags & CS_EP_KILL_CONN) {
 		TRACE_STATE("stream wants to kill the connection", H1_EV_STRM_SHUT, h1c->conn, h1s);
 		goto do_shutr;
 	}
@@ -3477,7 +3477,7 @@
 
   do_shutr:
 	/* NOTE: Be sure to handle abort (cf. h2_shutr) */
-	if (cs->flags & CS_FL_SHR)
+	if (cs->endp->flags & CS_EP_SHR)
 		goto end;
 
 	if (conn_xprt_ready(h1c->conn) && h1c->conn->xprt->shutr)
@@ -3497,9 +3497,9 @@
 
 	TRACE_ENTER(H1_EV_STRM_SHUT, h1c->conn, h1s, 0, (size_t[]){mode});
 
-	if (cs->flags & CS_FL_SHW)
+	if (cs->endp->flags & CS_EP_SHW)
 		goto end;
-	if (cs->flags & CS_FL_KILL_CONN) {
+	if (cs->endp->flags & CS_EP_KILL_CONN) {
 		TRACE_STATE("stream wants to kill the connection", H1_EV_STRM_SHUT, h1c->conn, h1s);
 		goto do_shutw;
 	}
@@ -3643,7 +3643,7 @@
 	else
 		TRACE_DEVEL("h1c ibuf not allocated", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
 
-	if ((flags & CO_RFL_BUF_FLUSH) && (cs->flags & CS_FL_MAY_SPLICE)) {
+	if ((flags & CO_RFL_BUF_FLUSH) && (cs->endp->flags & CS_EP_MAY_SPLICE)) {
 		h1c->flags |= H1C_F_WANT_SPLICE;
 		TRACE_STATE("Block xprt rcv_buf to flush stream's buffer (want_splice)", H1_EV_STRM_RECV, h1c->conn, h1s);
 	}
@@ -3783,7 +3783,7 @@
 
 	if (!(h1c->flags & H1C_F_WANT_SPLICE)) {
 		TRACE_STATE("notify the mux can't use splicing anymore", H1_EV_STRM_RECV, h1c->conn, h1s);
-		cs->flags &= ~CS_FL_MAY_SPLICE;
+		cs->endp->flags &= ~CS_EP_MAY_SPLICE;
 		if (!(h1c->wait_event.events & SUB_RETRY_RECV)) {
 			TRACE_STATE("restart receiving data, subscribing", H1_EV_STRM_RECV, h1c->conn, h1s);
 			h1c->conn->xprt->subscribe(h1c->conn, h1c->conn->xprt_ctx, SUB_RETRY_RECV, &h1c->wait_event);