virtio-vga: fix reset.

virtio-vga: fix reset.

Store reset handler of the parent class and just call that for a
complete virtio reset.  When taking the shortcut and calling
virtio_gpu_reset() directly the generic virtio reset code (for
virtqueues etc) will not be executed.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1597621
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20190307080244.9011-3-kraxel@redhat.com