Revert "drm/amdgpu: fix a potential deadlock in amdgpu_bo_create_restricted()"

This reverts commit 38fc4856, which
introduces a use-after-free.

The underlying bug should be properly fixed with "drm/ttm: never add BO
that failed to validate to the LRU list".

Cc: zhoucm1 <david1.zhou@amd.com>
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Tested-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>