libertas: register sysfs groups properly

The libertas driver was trying to register sysfs groups "by hand" which
causes them to be created _after_ the device is initialized and
announced to userspace, which causes races and can prevent userspace
tools from seeing the sysfs files correctly.

Fix this up by using the built-in sysfs_groups pointers in struct
net_device which were created for this very reason, fixing the race
condition, and properly allowing for any error that might have occured
to be handled properly.

Cc: Kalle Valo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/net/wireless/marvell/libertas/mesh.c

···
 	.attrs = mesh_ie_attrs,
 };
 
-static void lbs_persist_config_init(struct net_device *dev)
-{
-	int ret;
-	ret = sysfs_create_group(&(dev->dev.kobj), &boot_opts_group);
-	ret = sysfs_create_group(&(dev->dev.kobj), &mesh_ie_group);
-}
-
-static void lbs_persist_config_remove(struct net_device *dev)
-{
-	sysfs_remove_group(&(dev->dev.kobj), &boot_opts_group);
-	sysfs_remove_group(&(dev->dev.kobj), &mesh_ie_group);
-}
-
 
 /***************************************************************************
  * Initializing and starting, stopping mesh
···
 	SET_NETDEV_DEV(priv->mesh_dev, priv->dev->dev.parent);
 
 	mesh_dev->flags |= IFF_BROADCAST | IFF_MULTICAST;
+	mesh_dev->sysfs_groups[0] = &lbs_mesh_attr_group;
+	mesh_dev->sysfs_groups[1] = &boot_opts_group;
+	mesh_dev->sysfs_groups[2] = &mesh_ie_group;
+
 	/* Register virtual mesh interface */
 	ret = register_netdev(mesh_dev);
 	if (ret) {
···
 		goto err_free_netdev;
 	}
 
-	ret = sysfs_create_group(&(mesh_dev->dev.kobj), &lbs_mesh_attr_group);
-	if (ret)
-		goto err_unregister;
-
-	lbs_persist_config_init(mesh_dev);
-
 	/* Everything successful */
 	ret = 0;
 	goto done;
-
-err_unregister:
-	unregister_netdev(mesh_dev);
 
 err_free_netdev:
 	free_netdev(mesh_dev);
···
 
 	netif_stop_queue(mesh_dev);
 	netif_carrier_off(mesh_dev);
-	sysfs_remove_group(&(mesh_dev->dev.kobj), &lbs_mesh_attr_group);
-	lbs_persist_config_remove(mesh_dev);
 	unregister_netdev(mesh_dev);
 	priv->mesh_dev = NULL;
 	kfree(mesh_dev->ieee80211_ptr);