md: report device as congested when suspended

This should writeback from coming when the device is temporarily
suspended.

Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index a3dd3c8..26ba42a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -262,6 +262,12 @@
 	mddev->pers->quiesce(mddev, 0);
 }
 
+int mddev_congested(mddev_t *mddev, int bits)
+{
+	return mddev->suspended;
+}
+EXPORT_SYMBOL(mddev_congested);
+
 
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {