btrfs: Replace fs_info->delayed_workers workqueue with btrfs_workqueue.

Replace the fs_info->delayed_workers with the newly created
btrfs_workqueue.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2e1d6cf..fd07d03 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1334,7 +1334,7 @@
 				new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
-	btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
 	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
 			      new_pool_size);