ath9k: add fast-xmit support

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/init.c

@@ -827,6 +827,7 @@ static void ath9k_set_hw_capab(struct ath_softc *sc, struct ieee80211_hw *hw)
 	ieee80211_hw_set(hw, SIGNAL_DBM);
 	ieee80211_hw_set(hw, RX_INCLUDES_FCS);
 	ieee80211_hw_set(hw, HOST_BROADCAST_PS_BUFFERING);
+	ieee80211_hw_set(hw, SUPPORT_FAST_XMIT);
 
 	if (ath9k_ps_enable)
 		ieee80211_hw_set(hw, SUPPORTS_PS);