vdpa_sim has been fixed to not override the dma_map_ops in commit 6c3d329e6486 ("vdpa_sim: get rid of DMA ops"), so don't select the
symbol and don't depend on HAS_DMA.
Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Michael S. Tsirkin <mst@redhat.com>