virtio-gpu-3d: fix abnormal display after a warm reboot

When resetting virtio-gpu, virgl_renderer_reset() should be
called to ensure that the virglrenderer status is correct.

Signed-off-by: Guoqing Zhang <zhangguoqing.kernel@bytedance.com>
Reviewed-by: Qi <Liu&lt;liuqi.16@bytedance.com>
Message-id: 20200918111632.37354-1-zhangguoqing.kernel@bytedance.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>