Allow to configure more CPUs and nodes.

With clustered mode and AMD's big flat APIC mode there is no reason anymore to
limit the max number of CPUs to 8.  Increase the limit to 256 for now, which
is the current APIC limit. 

Untested for now.

Also increase the max number of nodes to 64.  Remove the MAXNODE define and
replace it with MAX_NUMNODES everywhere or the constant if the hardware limits
the number of nodes.

Also remove some obsolete comments.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>