net: marvell: prestera: fix missed deinit sequence

Add unregister_fib_notifier as rollback of register_fib_notifier.

Fixes: 4394fbcb ("net: marvell: prestera: handle fib notifications")
Signed-off-by: Yevhen Orlov <yevhen.orlov@plvision.eu>
Link: https://lore.kernel.org/r/20220710122021.7642-1-yevhen.orlov@plvision.euSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/marvell/prestera/prestera_router.c

@@ -588,6 +588,7 @@ int prestera_router_init(struct prestera_switch *sw)
 
 void prestera_router_fini(struct prestera_switch *sw)
 {
+	unregister_fib_notifier(&init_net, &sw->router->fib_nb);
 	unregister_inetaddr_notifier(&sw->router->inetaddr_nb);
 	unregister_inetaddr_validator_notifier(&sw->router->inetaddr_valid_nb);
 	rhashtable_destroy(&sw->router->kern_fib_cache_ht);