vl: add system_wakeup_request tracepoint

It might be useful for tracing migration.
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

trace-events

@@ -486,6 +486,7 @@ runstate_set(int new_state) "new state %d"
 g_malloc(size_t size, void *ptr) "size %zu ptr %p"
 g_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu newptr %p"
 g_free(void *ptr) "ptr %p"
+system_wakeup_request(int reason) "reason=%d"
 
 # block/qcow2.c
 qcow2_writev_start_req(void *co, int64_t sector, int nb_sectors) "co %p sector %" PRIx64 " nb_sectors %d"

vl.c

@@ -1837,6 +1837,8 @@ void qemu_register_suspend_notifier(Notifier *notifier)
 
 void qemu_system_wakeup_request(WakeupReason reason)
 {
+    trace_system_wakeup_request(reason);
+
     if (!runstate_check(RUN_STATE_SUSPENDED)) {
         return;
     }