mac80211: allow passing transmitter station on RX

Sometimes drivers already looked up, or know out-of-band
from their device, which station transmitted a given RX
frame. Allow them to pass the station pointer to mac80211
to save the extra lookup.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/dvm/rx.c

@@ -686,7 +686,7 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv,
 
 	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));
 
-	ieee80211_rx_napi(priv->hw, skb, priv->napi);
+	ieee80211_rx_napi(priv->hw, NULL, skb, priv->napi);
 }
 
 static u32 iwlagn_translate_rx_status(struct iwl_priv *priv, u32 decrypt_in)