drm_gem_object_put calls release_notify callback to free the mem
structure and unreserve_mem_limit, move it down after the last access
of mem and make it conditional call.
Signed-off-by: NPhilip Yang <Philip.Yang@amd.com>
Reviewed-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>