virtio-serial-bus: Delete timer from list before free it

Signed-off-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAmit Shah <amit@kernel.org>

hw/char/virtio-serial-bus.c

@@ -724,6 +724,7 @@ static void virtio_serial_post_load_timer_cb(void *opaque)
         }
     }
     g_free(s->post_load->connected);
+    timer_del(s->post_load->timer);
     timer_free(s->post_load->timer);
     g_free(s->post_load);
     s->post_load = NULL;