drm/amdgpu: fix vram reservation issue

The vram block allocation flag must be cleared
before making vram reservation, otherwise reserving
addresses within the currently freed memory range
will always fail.

Fixes: c9cad93 ("drm/amdgpu: add drm buddy support to amdgpu")
Signed-off-by: YiPeng Chai <YiPeng.Chai@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit d38eaf2)

Author: YiPeng Chai

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c

@@ -648,9 +648,8 @@ static void amdgpu_vram_mgr_del(struct ttm_resource_manager *man,
 	list_for_each_entry(block, &vres->blocks, link)
 		vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
 
-	amdgpu_vram_mgr_do_reserve(man);
-
 	drm_buddy_free_list(mm, &vres->blocks, vres->flags);
+	amdgpu_vram_mgr_do_reserve(man);
 	mutex_unlock(&mgr->lock);
 
 	atomic64_sub(vis_usage, &mgr->vis_usage);