Btrfs: cleanup fs_info->hashers

fs_info->hashers is now an obsolete one.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d66dc1c..1372057 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1253,7 +1253,6 @@
 	struct mutex reloc_mutex;
 
 	struct list_head trans_list;
-	struct list_head hashers;
 	struct list_head dead_roots;
 	struct list_head caching_block_groups;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8d633e3..5d3f813 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1984,7 +1984,6 @@
 	INIT_LIST_HEAD(&fs_info->trans_list);
 	INIT_LIST_HEAD(&fs_info->dead_roots);
 	INIT_LIST_HEAD(&fs_info->delayed_iputs);
-	INIT_LIST_HEAD(&fs_info->hashers);
 	INIT_LIST_HEAD(&fs_info->delalloc_inodes);
 	INIT_LIST_HEAD(&fs_info->ordered_operations);
 	INIT_LIST_HEAD(&fs_info->caching_block_groups);