[POWERPC] No DEEPNAP on 970MP 1.0

970MP rev 1.0 is reported to have nonworking DEEPNAP support, we've had
bug reports of lockups on those machines. Appearantly Apple used them
on some dual-core dual-cpu systems. Rev 1.1 is OK, and that's the one
that all 4-way systems seem to use.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>