PM / Runtime: Export the PM runtime workqueue

This patch (as1306) exports the PM runtime workqueue for use by
loadable modules.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

kernel/power/main.c

@@ -220,6 +220,7 @@ static struct attribute_group attr_group = {
 
 #ifdef CONFIG_PM_RUNTIME
 struct workqueue_struct *pm_wq;
+EXPORT_SYMBOL_GPL(pm_wq);
 
 static int __init pm_start_workqueue(void)
 {