mac80211: fix management frame protection issue with mt76 (and possibly other drivers)

Software crypto wasn't working for management frames because the flag
indicating management frame crypto was missing

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/kernel/mac80211/patches/subsys/350-mac80211-fix-setting-IEEE80211_KEY_FLAG_RX_MGMT-for-.patch

@@ -0,0 +1,25 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 29 Sep 2018 15:55:44 +0200
+Subject: [PATCH] mac80211: fix setting IEEE80211_KEY_FLAG_RX_MGMT for AP mode
+ keys
+
+key->sta is only valid after ieee80211_key_link, which is called later
+in this function. Because of that, the IEEE80211_KEY_FLAG_RX_MGMT is
+never set when management frame protection is enabled.
+
+Fixes: e548c49e6dc6b ("mac80211: add key flag for management keys")
+Cc: stable@vger.kernel.org
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/cfg.c
++++ b/net/mac80211/cfg.c
+@@ -427,7 +427,7 @@ static int ieee80211_add_key(struct wiph
+ 	case NL80211_IFTYPE_AP:
+ 	case NL80211_IFTYPE_AP_VLAN:
+ 		/* Keys without a station are used for TX only */
+-		if (key->sta && test_sta_flag(key->sta, WLAN_STA_MFP))
++		if (sta && test_sta_flag(sta, WLAN_STA_MFP))
+ 			key->conf.flags |= IEEE80211_KEY_FLAG_RX_MGMT;
+ 		break;
+ 	case NL80211_IFTYPE_ADHOC: