[PATCH] register_one_node() compile fix

register_one_node()'s should be defined under CONFIG_NUMA=n.
fixes following bug.

  CC	  init/version.o
  LD	  init/built-in.o
  LD	  .tmp_vmlinux1
  mm/built-in.o: In function `add_memory': undefined reference to `register_one_node'

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>