greybus: timesync/pm: Make synchronous call to restore FrameTime

When we discussed and agreed a serialized way to-do PM runtime
suspend/resume we omitted the necessity to restore the FrameTime on resume.
This patch restores the FrameTime synchronously such that when an Interface
PM resume callback completes we have either successfully restored the
FrameTime including the new Interface or we've produced a result code to
indicate what went wrong when trying.
Suggested-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Tested-by: David Lin <dtwlin@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/interface.c

@@ -579,6 +579,12 @@ static int gb_interface_resume(struct device *dev)
 		return ret;
 	}
 
+	ret = gb_timesync_schedule_synchronous(intf);
+	if (ret) {
+		dev_err(dev, "failed to synchronize FrameTime: %d\n", ret);
+		return ret;
+	}
+
 	return 0;
 }