net: clear skb->tstamp in bridge forwarding path

Matteo reported forwarding issues inside the linux bridge,
if the enslaved interfaces use the fq qdisc.

Similar to commit 8203e2d8 ("net: clear skb->tstamp in
forwarding paths"), we need to clear the tstamp field in
the bridge forwarding path.

Fixes: 80b14dee ("net: Add a new socket option for a future transmit time.")
Fixes: fb420d5d ("tcp/fq: move back to CLOCK_MONOTONIC")
Reported-and-tested-by: NMatteo Croce <mcroce@redhat.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_forward.c

@@ -65,6 +65,7 @@ EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
 
 int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
+	skb->tstamp = 0;
 	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
 		       net, sk, skb, NULL, skb->dev,
 		       br_dev_queue_push_xmit);