ath9k: Advertise support for AP mode channel width changes

This will enable AP mode to change channel width dynamically
based on 20/40 intolerance report sent by associated client.
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -714,7 +714,8 @@ static void ath9k_set_hw_capab(struct ath_softc *sc, struct ieee80211_hw *hw)
 	if (AR_SREV_9160_10_OR_LATER(sc->sc_ah) || ath9k_modparam_nohwcrypt)
 		hw->flags |= IEEE80211_HW_MFP_CAPABLE;
 
-	hw->wiphy->features |= NL80211_FEATURE_ACTIVE_MONITOR;
+	hw->wiphy->features |= (NL80211_FEATURE_ACTIVE_MONITOR |
+				NL80211_FEATURE_AP_MODE_CHAN_WIDTH_CHANGE);
 
 	if (!config_enabled(CONFIG_ATH9K_TX99)) {
 		hw->wiphy->interface_modes =