This allows fine grained control for the driver where to add a BO into the LRU.

v2: fix typo in comment
Reviewed-by: NSinclair Yeh <syeh@vmware.com>
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>