cfg80211: reject HT/VHT capabilities on 6 GHz band

On the 6 GHz band, HE should be used, but without any direct HT/VHT
capabilities, instead the HE 6 GHz band capabilities will capture
the relevant information. Reject HT/VHT capabilities here.

Link: https://lore.kernel.org/r/20200528213443.bfe89c35459a.Ibba5e066fa0087fd49d13cfee89d196ea0c68ae2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/core.c

@@ -5,7 +5,7 @@
  * Copyright 2006-2010		Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
  * Copyright 2015-2017	Intel Deutschland GmbH
- * Copyright (C) 2018-2019 Intel Corporation
+ * Copyright (C) 2018-2020 Intel Corporation
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -807,6 +807,11 @@ int wiphy_register(struct wiphy *wiphy)
 			    !sband->n_bitrates))
 			return -EINVAL;
 
+		if (WARN_ON(band == NL80211_BAND_6GHZ &&
+			    (sband->ht_cap.ht_supported ||
+			     sband->vht_cap.vht_supported)))
+			return -EINVAL;
+
 		/*
 		 * Since cfg80211_disable_40mhz_24ghz is global, we can
 		 * modify the sband's ht data even if the driver uses a