qcacmn: Fix MLO link stats issues

Add link_id check while aggregatin stats into vdev at 
time of peer unmap, otherwise vdev stats are aggregated 
twice and hence give incorrect output.

Also comment out link_id fetch in BE Rx path as it is 
currently not enabled.

Change-Id: I91ceab4c6380bbd6e0cb2717adb2413e9e8e4221
CRs-Fixed: 3435688

dp/wifi3.0/dp_stats.c

@@ -8565,10 +8565,11 @@ void dp_update_vdev_stats_on_peer_unmap(struct dp_vdev *vdev,
 
 	if (IS_MLO_DP_LINK_PEER(peer)) {
 		link_id = dp_get_peer_hw_link_id(soc, pdev);
-		per_pkt_stats = &txrx_peer->
-				stats[link_id].per_pkt_stats;
-		DP_UPDATE_PER_PKT_STATS(vdev_stats,
-					per_pkt_stats);
+		if (link_id > 0) {
+			per_pkt_stats =
+				&txrx_peer->stats[link_id].per_pkt_stats;
+			DP_UPDATE_PER_PKT_STATS(vdev_stats, per_pkt_stats);
+		}
 	}
 
 link_stats: