drm/qxl: use ttm_tt

qxl device will not dma, so we don't need ttm_dma_tt.  Go use ttm_tt
instead, to avoid wasting resources (swiotlb bounce buffers for
example).
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20190129082541.1392-1-kraxel@redhat.com

drivers/gpu/drm/qxl/qxl_ttm.c

@@ -204,7 +204,7 @@ static void qxl_ttm_io_mem_free(struct ttm_bo_device *bdev,
  * TTM backend functions.
  */
 struct qxl_ttm_tt {
-	struct ttm_dma_tt		ttm;
+	struct ttm_tt		        ttm;
 	struct qxl_device		*qdev;
 	u64				offset;
 };
@@ -233,7 +233,7 @@ static void qxl_ttm_backend_destroy(struct ttm_tt *ttm)
 {
 	struct qxl_ttm_tt *gtt = (void *)ttm;
 
-	ttm_dma_tt_fini(&gtt->ttm);
+	ttm_tt_fini(&gtt->ttm);
 	kfree(gtt);
 }
 
@@ -253,13 +253,13 @@ static struct ttm_tt *qxl_ttm_tt_create(struct ttm_buffer_object *bo,
 	gtt = kzalloc(sizeof(struct qxl_ttm_tt), GFP_KERNEL);
 	if (gtt == NULL)
 		return NULL;
-	gtt->ttm.ttm.func = &qxl_backend_func;
+	gtt->ttm.func = &qxl_backend_func;
 	gtt->qdev = qdev;
-	if (ttm_dma_tt_init(&gtt->ttm, bo, page_flags)) {
+	if (ttm_tt_init(&gtt->ttm, bo, page_flags)) {
 		kfree(gtt);
 		return NULL;
 	}
-	return &gtt->ttm.ttm;
+	return &gtt->ttm;
 }
 
 static void qxl_move_null(struct ttm_buffer_object *bo,