As noted by Olof Johansson <olof@lixom.net>:

  "A recent patch changed the way the LPAR bit is checked during early
   boot.  This resulted in a polarity change in a conditional branch
   without changing the branch, causing at least some legacy machines to
   not boot."

This fixes it.
Signed-off-by: Jimi Xenidis <jimix@watson.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>