mac80211: calculate skb hash early when using itxq

This avoids flow separation issues when using software encryption.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20200726130947.88145-2-nbd@nbd.nameSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -3952,6 +3952,7 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
 	if (local->ops->wake_tx_queue) {
 		u16 queue = __ieee80211_select_queue(sdata, sta, skb);
 		skb_set_queue_mapping(skb, queue);
+		skb_get_hash(skb);
 	}
 
 	if (sta) {