mei: bus: fix notification event delivery

Call wake_up cl->ev_wait only in case there is no bus client registered
to the event notification.
Second, since we don't have exclusive waiter wake_up_interruptible_all
is not used correctly here.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index a40d8e2..990f4f6 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -230,25 +230,30 @@
  * mei_cl_bus_notify_event - schedule notify cb on bus client
  *
  * @cl: host client
+ *
+ * Return: true if event was scheduled
+ *         false if the client is not waiting for event
  */
-void mei_cl_bus_notify_event(struct mei_cl *cl)
+bool mei_cl_bus_notify_event(struct mei_cl *cl)
 {
 	struct mei_cl_device *cldev = cl->cldev;
 
 	if (!cldev || !cldev->event_cb)
-		return;
+		return false;
 
 	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)))
-		return;
+		return false;
 
 	if (!cl->notify_ev)
-		return;
+		return false;
 
 	set_bit(MEI_CL_EVENT_NOTIF, &cldev->events);
 
 	schedule_work(&cldev->event_work);
 
 	cl->notify_ev = false;
+
+	return true;
 }
 
 /**