btrfs: remove all unused functions

Remove static and global declarations and/or definitions. Reduces size
of btrfs.ko by ~3.4kB.

  text    data     bss     dec     hex filename
402081    7464     200  409745   64091 btrfs.ko.base
398620    7144     200  405964   631cc btrfs.ko.remove-all

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index f7b799b..f726e72 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -507,6 +507,7 @@
 	return 1;
 }
 
+
 static int should_ignore_root(struct btrfs_root *root)
 {
 	struct btrfs_root *reloc_root;
@@ -529,7 +530,6 @@
 	 */
 	return 1;
 }
-
 /*
  * find reloc tree by address of tree root
  */