mac80211: fix TCP performance on mesh interface

sta is NULL for mesh point (resolved later), so sk pacing parameters
were not applied.

Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Link: https://lore.kernel.org/r/66f51659416ac35d6b11a313bd3ffe8b8a43dd55.camel@freebox.fr
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -4191,11 +4191,11 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
 
 	ieee80211_aggr_check(sdata, sta, skb);
 
+	sk_pacing_shift_update(skb->sk, sdata->local->hw.tx_sk_pacing_shift);
+
 	if (sta) {
 		struct ieee80211_fast_tx *fast_tx;
 
-		sk_pacing_shift_update(skb->sk, sdata->local->hw.tx_sk_pacing_shift);
-
 		fast_tx = rcu_dereference(sta->fast_tx);
 
 		if (fast_tx &&