smp: set tsi in fakewsi used with WAIT_CANCELLED

Together with the new lws_wsi_tsi(wsi) this lets the WAIT_CANCELLED
callback understand its tsi context, the broadcasts are done for each
pt / loop.

lib/core-net/wsi.c

@@ -610,8 +610,10 @@ lws_broadcast(struct lws_context_per_thread *pt, int reason, void *in, size_t le
 	lws_fakewsi_def_plwsa(pt);
 	int n, ret = 0;
 
-
 	lws_fakewsi_prep_plwsa_ctx(pt->context);
+#if !defined(LWS_PLAT_FREERTOS) && LWS_MAX_SMP > 1
+	((struct lws *)plwsa)->tsi = (int)(pt - &pt->context->pt[0]);
+#endif
 
 	while (v) {
 		const struct lws_protocols *p = v->protocols;