Use object_dynamic_cast() to determine if 'dev' is a TYPE_VIRTIO_MMIO.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>