device: fix ref leak in controller_release_port when detach completes synchronously

When detach_port() returns a value other than NM_TERNARY_DEFAULT,
the g_object_ref(port) passed as user_data for the async callback
is never released.

Fixes: 07dc237e5c ('device: wait port detach before leaving the DEACTIVATING state')

src/core/devices/nm-device.c

@@ -7278,6 +7278,8 @@ nm_device_controller_release_port(NMDevice           *self,
         if (ret == NM_TERNARY_DEFAULT) {
             port_priv->port_detach_count++;
             port_priv->port_detach_reason = reason;
+        } else {
+            g_object_unref(port);
         }
     }