[POWERPC] Celleb: New HTAB Guest OS Interface on Beat

This changes the Celleb code to work with new Guest OS Interface
to tweak HTAB on Beat. It detects old and new Guest OS Interfaces
automatically.

Signed-off-by: Kou Ishizaki <Kou.Ishizaki@toshiba.co.jp>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>