cpu-hotplug: export cpu_hotplug_enable/cpu_hotplug_disable

Hyper-V module needs to disable cpu hotplug (offlining) as there is no
support from hypervisor side to reassign already opened event channels
to a different CPU. Currently it is been done by altering
smp_ops.cpu_disable but it is hackish.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/cpu.c

@@ -194,14 +194,15 @@ void cpu_hotplug_disable(void)
 	cpu_hotplug_disabled++;
 	cpu_maps_update_done();
 }
+EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
 
 void cpu_hotplug_enable(void)
 {
 	cpu_maps_update_begin();
 	WARN_ON(--cpu_hotplug_disabled < 0);
 	cpu_maps_update_done();
 }
-
+EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
 #endif	/* CONFIG_HOTPLUG_CPU */
 
 /* Need to know about CPUs going up/down? */