qcacmn: Add NULL check for delay stats

Add NULL check for delay stats in txrx_peer

Change-Id: I3852be1b112a9a105af57890d1636d86a747b2ab
CRs-Fixed: 3365940

dp/wifi3.0/dp_tx.c

@@ -4297,10 +4297,12 @@ static void dp_tx_update_peer_delay_stats(struct dp_txrx_peer *txrx_peer,
 	if (qdf_likely(!wlan_cfg_is_peer_ext_stats_enabled(soc->wlan_cfg_ctx)))
 		return;
 
+	if (!txrx_peer->delay_stats)
+		return;
+
 	tid = ts->tid;
 	delay_stats = txrx_peer->delay_stats;
 
-	qdf_assert(delay_stats);
 	qdf_assert(ring < CDP_MAX_TXRX_CTX);
 
 	/*