drm/radeon: fix prime teardown order

We unmapped imported DMA-bufs when the GEM handle was dropped, not when the
hardware was done with the buffere.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
CC: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_gem.c

@@ -34,8 +34,6 @@ void radeon_gem_object_free(struct drm_gem_object *gobj)
 	struct radeon_bo *robj = gem_to_radeon_bo(gobj);
 
 	if (robj) {
-		if (robj->gem_base.import_attach)
-			drm_prime_gem_destroy(&robj->gem_base, robj->tbo.sg);
 		radeon_mn_unregister(robj);
 		radeon_bo_unref(&robj);
 	}

drivers/gpu/drm/radeon/radeon_object.c

@@ -82,6 +82,8 @@ static void radeon_ttm_bo_destroy(struct ttm_buffer_object *tbo)
 	mutex_unlock(&bo->rdev->gem.mutex);
 	radeon_bo_clear_surface_reg(bo);
 	WARN_ON_ONCE(!list_empty(&bo->va));
+	if (bo->gem_base.import_attach)
+		drm_prime_gem_destroy(&bo->gem_base, bo->tbo.sg);
 	drm_gem_object_release(&bo->gem_base);
 	kfree(bo);
 }