drm/radeon: unbind in radeon_ttm_tt_unpopulate()

Doing this in radeon_ttm_tt_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/20210728130552.2074-4-christian.koenig@amd.com

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -488,9 +488,7 @@ static void radeon_ttm_backend_destroy(struct ttm_device *bdev, struct ttm_tt *t
 {
 	struct radeon_ttm_tt *gtt = (void *)ttm;
 
-	radeon_ttm_backend_unbind(bdev, ttm);
 	ttm_tt_destroy_common(bdev, ttm);
-
 	ttm_tt_fini(&gtt->ttm);
 	kfree(gtt);
 }
@@ -574,6 +572,8 @@ static void radeon_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm
 	struct radeon_ttm_tt *gtt = radeon_ttm_tt_to_gtt(rdev, ttm);
 	bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
 
+	radeon_ttm_tt_unbind(bdev, ttm);
+
 	if (gtt && gtt->userptr) {
 		kfree(ttm->sg);
 		ttm->page_flags &= ~TTM_PAGE_FLAG_SG;
@@ -651,7 +651,6 @@ static void radeon_ttm_tt_destroy(struct ttm_device *bdev,
 	struct radeon_device *rdev = radeon_get_rdev(bdev);
 
 	if (rdev->flags & RADEON_IS_AGP) {
-		ttm_agp_unbind(ttm);
 		ttm_tt_destroy_common(bdev, ttm);
 		ttm_agp_destroy(ttm);
 		return;