x86, xen: fix build when !CONFIG_HOTPLUG_CPU

Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/xen/smp.c

@@ -332,6 +332,7 @@ static void xen_smp_cpus_done(unsigned int max_cpus)
 {
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
 int xen_cpu_disable(void)
 {
 	unsigned int cpu = smp_processor_id();
@@ -368,6 +369,23 @@ void xen_play_dead(void)
 	cpu_bringup();
 }
 
+#else /* !CONFIG_HOTPLUG_CPU */
+int xen_cpu_disable(void)
+{
+	return -ENOSYS;
+}
+
+void xen_cpu_die(unsigned int cpu)
+{
+	BUG();
+}
+
+void xen_play_dead(void)
+{
+	BUG();
+}
+
+#endif
 static void stop_self(void *v)
 {
 	int cpu = smp_processor_id();