virtio-gpu: Handle virtio_gpu_virgl_init() failure

virtio-gpu: Handle virtio_gpu_virgl_init() failure

virtio_gpu_virgl_init() may fail, leading to a further Qemu crash
because Qemu assumes it never fails. Check virtio_gpu_virgl_init()
return code and don't execute virtio commands on error. Failed
virtio_gpu_virgl_init() will result in a timed out virtio commands
for a guest OS.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Message-Id: <20241024210311.118220-5-dmitry.osipenko@collabora.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>