mac80211: Support BIGTK configuration for Beacon protection

Extend mac80211 key configuration to support the new BIGTK with key
index values 6 and 7. Support for actually protecting Beacon frames
(adding the MME in AP mode and checking it in STA mode) is covered in
separate commits.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Link: https://lore.kernel.org/r/20200222132548.20835-3-jouni@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/sta_info.h

@@ -533,7 +533,9 @@ struct sta_info {
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
-	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
+	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS +
+					NUM_DEFAULT_MGMT_KEYS +
+					NUM_DEFAULT_BEACON_KEYS];
 	struct ieee80211_key __rcu *ptk[NUM_DEFAULT_KEYS];
 	u8 ptk_idx;
 	struct rate_control_ref *rate_ctrl;