savevm: Add DeviceState param

When available, we'd like to be able to access the DeviceState
when registering a savevm.  For buses with a get_dev_path()
function, this will allow us to create more unique savevm
id strings.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qemu-timer.c b/qemu-timer.c
index bdc8206..bc5f207 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -662,7 +662,7 @@
 
 void configure_icount(const char *option)
 {
-    vmstate_register(0, &vmstate_timers, &timers_state);
+    vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
     if (!option)
         return;