Some earlier models of aluminium powerbooks and ibook G4s have a clock chip
that requires some tweaking before and after sleep.  It seems that without
that magic incantation to disable and re-enable clock spreading, RAM isn't
properly refreshed during sleep.  This fixes it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>