xen: don't use flush_scheduled_work()

flush_scheduled_work() is deprecated and scheduled to be removed.
Directly flush info->work instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/block/xen-blkfront.c

@@ -538,7 +538,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info)
 	spin_unlock_irqrestore(&blkif_io_lock, flags);
 
 	/* Flush gnttab callback work. Must be done with no locks held. */
-	flush_scheduled_work();
+	flush_work_sync(&info->work);
 
 	del_gendisk(info->gd);
 
@@ -587,7 +587,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
 	spin_unlock_irq(&blkif_io_lock);
 
 	/* Flush gnttab callback work. Must be done with no locks held. */
-	flush_scheduled_work();
+	flush_work_sync(&info->work);
 
 	/* Free resources associated with old device channel. */
 	if (info->ring_ref != GRANT_INVALID_REF) {