mac80211_hwsim: fix module init error paths for netlink

There is no unregister netlink notifier and family on error paths
in init_mac80211_hwsim(). Also there is an error path where
hwsim_class is not destroyed.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 62759361 ("mac80211-hwsim: Provide multicast event for HWSIM_CMD_NEW_RADIO")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -3703,16 +3703,16 @@ static int __init init_mac80211_hwsim(void)
 	if (err)
 		goto out_unregister_pernet;
 
+	err = hwsim_init_netlink();
+	if (err)
+		goto out_unregister_driver;
+
 	hwsim_class = class_create(THIS_MODULE, "mac80211_hwsim");
 	if (IS_ERR(hwsim_class)) {
 		err = PTR_ERR(hwsim_class);
-		goto out_unregister_driver;
+		goto out_exit_netlink;
 	}
 
-	err = hwsim_init_netlink();
-	if (err < 0)
-		goto out_unregister_driver;
-
 	for (i = 0; i < radios; i++) {
 		struct hwsim_new_radio_params param = { 0 };
 
@@ -3818,6 +3818,8 @@ static int __init init_mac80211_hwsim(void)
 	free_netdev(hwsim_mon);
 out_free_radios:
 	mac80211_hwsim_free();
+out_exit_netlink:
+	hwsim_exit_netlink();
 out_unregister_driver:
 	platform_driver_unregister(&mac80211_hwsim_driver);
 out_unregister_pernet: