nl80211: fix NL80211_ATTR_HE_6GHZ_CAPABILITY usage

In nl80211_set_station(), we check NL80211_ATTR_HE_6GHZ_CAPABILITY
and then use NL80211_ATTR_HE_CAPABILITY, which is clearly wrong.
Fix this to use NL80211_ATTR_HE_6GHZ_CAPABILITY as well.

Cc: stable@vger.kernel.org
Fixes: 43e64bf3 ("cfg80211: handle 6 GHz capability of new station")
Link: https://lore.kernel.org/r/20200805153516.310cef625955.I0abc04dc8abb2c7c005c88ef8fa2d0e3c9fb95c4@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -6011,7 +6011,7 @@ static int nl80211_set_station(struct sk_buff *skb, struct genl_info *info)
 
 	if (info->attrs[NL80211_ATTR_HE_6GHZ_CAPABILITY])
 		params.he_6ghz_capa =
-			nla_data(info->attrs[NL80211_ATTR_HE_CAPABILITY]);
+			nla_data(info->attrs[NL80211_ATTR_HE_6GHZ_CAPABILITY]);
 
 	if (info->attrs[NL80211_ATTR_AIRTIME_WEIGHT])
 		params.airtime_weight =