This leads to bootmem allocating first from node 0 instead
of from the last node.  This avoids swiotlb allocating on the last node, which
doesn't really work on a machine with >4GB.

Note: there is a better patch around from someone else that gets
rid of the pgdat list completely.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>