virgl: Use file descriptor instead of un-allocated object

The structure qdws is not allocated at this point, nor is the
file descriptor set to it's member. Use the fd directly instead.

Fixes:  d1a1c21e76
    virgl: native fence fd support

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>

src/gallium/winsys/virgl/drm/virgl_drm_winsys.c

@@ -892,7 +892,7 @@ virgl_drm_winsys_create(int drmFD)
    if (ret < 0 || !gl)
       return NULL;
 
-   drm_version = virgl_drm_get_version(qdws->fd);
+   drm_version = virgl_drm_get_version(drmFD);
    if (drm_version < 0)
       return NULL;