mac80211: skip legacy rate mask handling for VHT rates

The rate mask code currently assumes that a rate is legacy if
IEEE80211_TX_RC_MCS is not set. This might be the cause of bogus VHT
rates being reported with minstrel_ht.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rate.c

@@ -385,7 +385,7 @@ static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
 			*rate = alt_rate;
 			return;
 		}
-	} else {
+	} else if (!(rate->flags & IEEE80211_TX_RC_VHT_MCS)) {
 		/* handle legacy rates */
 		if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
 			return;