mac80211: support (partial) VHT radiotap information

Add some information that we have about VHT to radiotap.
This at least lets one see the MCS and NSS information.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 6e93340..c4ed83b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -638,6 +638,8 @@
 	local->hw.radiotap_mcs_details = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
 					 IEEE80211_RADIOTAP_MCS_HAVE_GI |
 					 IEEE80211_RADIOTAP_MCS_HAVE_BW;
+	local->hw.radiotap_vht_details = IEEE80211_RADIOTAP_VHT_KNOWN_GI |
+					 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
 	local->user_power_level = IEEE80211_UNSET_POWER_LEVEL;
 	wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;