drm/amdgpu: fix amdgpu_bo_unreserve order in GEM_OP IOCTL v2

No copy_(to|from)_user while BO is reserved.

v2: handle default path as well

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>