hv: switch to cpuhp state machine for synic init/cleanup

To make it possible to online/offline CPUs switch to cpuhp infrastructure
for doing hv_synic_init()/hv_synic_cleanup().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 27982df..83beea7 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -505,9 +505,9 @@
 
 extern void hv_synic_free(void);
 
-extern void hv_synic_init(void *irqarg);
+extern int hv_synic_init(unsigned int cpu);
 
-extern void hv_synic_cleanup(void *arg);
+extern int hv_synic_cleanup(unsigned int cpu);
 
 extern void hv_synic_clockevents_cleanup(void);