cfg80211: mesh: track (and thus validate) beacon interval

This is needed for beacon interval validation; if we don't
store it, then new interfaces added won't validate that the
beacon interval is the same as existing ones. Fix this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/mesh.c

@@ -183,6 +183,7 @@ int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
 		memcpy(wdev->ssid, setup->mesh_id, setup->mesh_id_len);
 		wdev->mesh_id_len = setup->mesh_id_len;
 		wdev->chandef = setup->chandef;
+		wdev->beacon_interval = setup->beacon_interval;
 	}
 
 	return err;
@@ -258,6 +259,7 @@ int __cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
 	err = rdev_leave_mesh(rdev, dev);
 	if (!err) {
 		wdev->mesh_id_len = 0;
+		wdev->beacon_interval = 0;
 		memset(&wdev->chandef, 0, sizeof(wdev->chandef));
 		rdev_set_qos_map(rdev, dev, NULL);
 	}