wifi: mt76: mt7996: enable VHT extended NSS BW feature

Set SUPPORTS_VHT_EXT_NSS_BW to let the max BW capability correctly be
parsed by different devices.
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7996/init.c

@@ -218,6 +218,8 @@ mt7996_init_wiphy(struct ieee80211_hw *hw)
 			IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
 		phy->mt76->sband_5g.sband.ht_cap.ampdu_density =
 			IEEE80211_HT_MPDU_DENSITY_1;
+
+		ieee80211_hw_set(hw, SUPPORTS_VHT_EXT_NSS_BW);
 	}
 
 	mt76_set_stream_caps(phy->mt76, true);