login: adjust range of InhibitWhat in assertions

src/login/logind-dbus.c

@@ -1656,7 +1656,7 @@ int bus_manager_shutdown_or_sleep_now_or_later(
         assert(m);
         assert(unit_name);
         assert(w > 0);
-        assert(w <= _INHIBIT_WHAT_MAX);
+        assert(w < _INHIBIT_WHAT_MAX);
         assert(!m->action_job);
 
         r = unit_load_state(m->bus, unit_name, &load_state);