[IA64] Clear up section mismatch with arch_unregister_cpu()

The generic_defconfig has three section mismatches.  This clears
arch_unregister_cpu()
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/topology.c

@@ -53,10 +53,12 @@ int __ref arch_register_cpu(int num)
 }
 EXPORT_SYMBOL(arch_register_cpu);
 
-void arch_unregister_cpu(int num)
+void __ref arch_unregister_cpu(int num)
 {
 	unregister_cpu(&sysfs_cpus[num].cpu);
+#ifdef CONFIG_ACPI
 	unmap_cpu_from_node(num, cpu_to_node(num));
+#endif
 }
 EXPORT_SYMBOL(arch_unregister_cpu);
 #else