[PATCH] Move node pgdat into node's own memory

[PATCH] Move node pgdat into node's own memory

Patch from William Lee Irwin

This moves the node's pgdat into the node's own local memory area along
with the lmem_map.

It only touches arch/i386/mm/discontig.c - ie can only affect NUMA
machines.  Has been tested in my tree for over a month on UP, SMP, and
NUMA and compile tested against a variety of different configs.