hw/display: report an error if virgl initialization failed

Currently, virgl initialization error is silent. Make it verbose instead.

(this is likely going to bug later on, as the device isn't fully
initialized)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

hw/display/virtio-gpu-virgl.c

@@ -609,6 +609,7 @@ int virtio_gpu_virgl_init(VirtIOGPU *g)
 
     ret = virgl_renderer_init(g, 0, &virtio_gpu_3d_cbs);
     if (ret != 0) {
+        error_report("virgl could not be initialized: %d", ret);
         return ret;
     }