ACPI: avoid references to impossible processors.

ACPI uses NR_CPUS in various loops and in some it accesses per cpu data of
processors that are not present(!) and that will never be present.

The pointers to per cpu data are typically not initialized for processors
that are not present.  So we seem to be reading something here from offset
0 in memory.

Make ACPI use nr_cpu_ids instead. That stops at the end of the possible
processors.

Convert one loop to NR_CPUS to use the cpu_possible map instead.  That way
ranges of processor that can never be brought online are skipped during the
loop.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>