[IA64] fix section mismatch in arch/ia64/kernel/topology.c

This patch silences:

	WARNING: vmlinux.o(.text+0x44672): Section mismatch in
	reference from the function arch_register_cpu() to the
	function .cpuinit.text:register_cpu()

Changes are based on codes in arch/x86/kernel/topology.c

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c
index abb17a6..26228e2 100644
--- a/arch/ia64/kernel/topology.c
+++ b/arch/ia64/kernel/topology.c
@@ -36,9 +36,11 @@
 }
 EXPORT_SYMBOL_GPL(arch_fix_phys_package_id);
 
-int arch_register_cpu(int num)
+
+#ifdef CONFIG_HOTPLUG_CPU
+int __ref arch_register_cpu(int num)
 {
-#if defined (CONFIG_ACPI) && defined (CONFIG_HOTPLUG_CPU)
+#ifdef CONFIG_ACPI
 	/*
 	 * If CPEI can be re-targetted or if this is not
 	 * CPEI target, then it is hotpluggable
@@ -47,19 +49,21 @@
 		sysfs_cpus[num].cpu.hotpluggable = 1;
 	map_cpu_to_node(num, node_cpuid[num].nid);
 #endif
-
 	return register_cpu(&sysfs_cpus[num].cpu, num);
 }
-
-#ifdef CONFIG_HOTPLUG_CPU
+EXPORT_SYMBOL(arch_register_cpu);
 
 void arch_unregister_cpu(int num)
 {
 	unregister_cpu(&sysfs_cpus[num].cpu);
 	unmap_cpu_from_node(num, cpu_to_node(num));
 }
-EXPORT_SYMBOL(arch_register_cpu);
 EXPORT_SYMBOL(arch_unregister_cpu);
+#else
+static int __init arch_register_cpu(int num)
+{
+	return register_cpu(&sysfs_cpus[num].cpu, num);
+}
 #endif /*CONFIG_HOTPLUG_CPU*/