ath9k_htc: use non-QoS NDP for AP probing

When switching mac80211 to use QoS NDP, it turned out that
ath9k_htc is somehow broken by this, e.g. see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891060.

Fix this by using the new mac80211 flag to go back to the
old, incorrect, behaviour for this driver.

Fixes: 7b6ddeaf ("mac80211: use QoS NDP for AP probing")
Reported-by: Ben Caradoc-Davies <ben@transient.nz>
Acked-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -729,6 +729,7 @@ static void ath9k_set_hw_capab(struct ath9k_htc_priv *priv,
 	ieee80211_hw_set(hw, SPECTRUM_MGMT);
 	ieee80211_hw_set(hw, SIGNAL_DBM);
 	ieee80211_hw_set(hw, AMPDU_AGGREGATION);
+	ieee80211_hw_set(hw, DOESNT_SUPPORT_QOS_NDP);
 
 	if (ath9k_ps_enable)
 		ieee80211_hw_set(hw, SUPPORTS_PS);