ichwd: add support for clearing No Reboot bit in TCOv4

This is based on a patch developed by
Tetsuya Uemura <t_uemura@macome.co.jp>.
Many thanks!

Submitted by: Tetsuya Uemura <t_uemura@macome.co.jp> (earlier version)
Tested by: Tetsuya Uemura <t_uemura@macome.co.jp>
MFC after: 2 weeks