[PATCH] Revert "drm/virtio: drop prime import/export callbacks"

[Gerd Hoffmann]

  Hi,

> > The DRI3 code extensively uses prime_handle_to_fd and
> > prime_fd_to_handle for self-import.

The callbacks are not used for self-import.

> I believe the cap was removed because the driver only supports
> self-import.  But the driver only runs inside VMs where there is no(?)
> other dma-buf clients,

There can be other dma-buf clients even in a VM.

cheers,
  Gerd