udmabuf: use cache_sgt_mapping option

The GEM prime helpers do it, so should we. It's also possible to make
it optional later.
Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20191203013627.85991-1-gurchetansingh@chromium.orgSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/dma-buf/udmabuf.c

@@ -94,6 +94,7 @@ static void release_udmabuf(struct dma_buf *buf)
 }
 
 static const struct dma_buf_ops udmabuf_ops = {
+	.cache_sgt_mapping = true,
 	.map_dma_buf	   = map_udmabuf,
 	.unmap_dma_buf	   = unmap_udmabuf,
 	.release	   = release_udmabuf,