[PATCH] x86-64: set node_possible_map at runtime - try 2

Set the node_possible_map at runtime on x86_64.  On a non NUMA system,
num_possible_nodes() will now say '1'.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>