PM / suspend: Print debug messages for device using direct-complete

Devices using the direct-complete optimization are not present it
debug messages printed by the core device suspend and resume code,
which sometimes makes it difficult to diagnose problems related to
them, so add debug messages for those devices.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/main.c

@@ -1741,8 +1741,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (dev->power.direct_complete) {
 		if (pm_runtime_status_suspended(dev)) {
 			pm_runtime_disable(dev);
-			if (pm_runtime_status_suspended(dev))
+			if (pm_runtime_status_suspended(dev)) {
+				pm_dev_dbg(dev, state, "direct-complete ");
 				goto Complete;
+			}
 
 			pm_runtime_enable(dev);
 		}