[PATCH] for_each_online_pgdat: remove pgdat_list

By using for_each_online_pgdat(), pgdat_list is not necessary now.  This patch
removes it.

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>