[PATCH] cpumask: export node_to_cpu_mask consistently

cpumask: ensure that node_to_cpumask() is available to modules for all
supported combinations of architecture and CONFIG_NUMA.

Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>