Use of "preorder" and "postorder" was incorrect. The callbacks are
simply invoked during tree ascent and descent during the
depth-first walk.
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>