Because pgdat_list was linked to pgdat_list in *reverse* order, (By default)
some of arch has to sort it by themselves.

for_each_pgdat has gone..for_each_online_pgdat() uses node_online_map, which
doesn't need to be sorted.

This patch removes codes for sorting pgdat.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>