This patch puts back the export of machine_power_off() that was removed
by some janitor as it's used for emergency shutdown by the G5 thermal
control driver. Wether that driver should use kernel_power_off() instead
is debatable and a post-2.6.13 decision. In the meantime, please commit
that patch that fixes the driver for now.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>