arch/x86/mm/numa_64.c: section fix

WARNING: vmlinux.o(__ksymtab+0x670): Section mismatch: reference to .init.data:x86_cpu_to_node_map_init (between '__ksymtab_x86_cpu_to_node_map_init' and '__ksymtab_node_data')

Cc: Matthew Dobson <colpatch@us.ibm.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>