drm/vmwgfx: unbind in vmw_ttm_unpopulate

Doing this in vmw_ttm_destroy() is to late.

It turned out that this is not a good idea at all because it leaves pointers
to freed up system memory pages in the GART tables of the drivers.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210728130552.2074-1-christian.koenig@amd.com

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c

@@ -526,14 +526,9 @@ static void vmw_ttm_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 	struct vmw_ttm_tt *vmw_be =
 		container_of(ttm, struct vmw_ttm_tt, dma_ttm);
 
-	vmw_ttm_unbind(bdev, ttm);
 	ttm_tt_destroy_common(bdev, ttm);
 	vmw_ttm_unmap_dma(vmw_be);
-	if (vmw_be->dev_priv->map_mode == vmw_dma_alloc_coherent)
-		ttm_tt_fini(&vmw_be->dma_ttm);
-	else
 	ttm_tt_fini(ttm);
-
 	if (vmw_be->mob)
 		vmw_mob_destroy(vmw_be->mob);
 
@@ -578,6 +573,8 @@ static void vmw_ttm_unpopulate(struct ttm_device *bdev,
 						 dma_ttm);
 	unsigned int i;
 
+	vmw_ttm_unbind(bdev, ttm);
+
 	if (vmw_tt->mob) {
 		vmw_mob_destroy(vmw_tt->mob);
 		vmw_tt->mob = NULL;