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.h b/drivers/md/md.h
index f55d2ff..f184b69 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -430,6 +430,7 @@
 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
 
+extern int mddev_congested(mddev_t *mddev, int bits);
 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
 			   sector_t sector, int size, struct page *page);
 extern void md_super_wait(mddev_t *mddev);