btrfs: remove blocksize from btrfs_alloc_free_block and rename

Rename to btrfs_alloc_tree_block as it fits to the alloc/find/free +
_tree_block family. The parameter blocksize was set to the metadata
block size, directly or indirectly.

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 089f6da..3073b88 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3290,9 +3290,9 @@
 						 u64 bytenr);
 void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
 int get_block_group_index(struct btrfs_block_group_cache *cache);
-struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
-					struct btrfs_root *root, u32 blocksize,
-					u64 parent, u64 root_objectid,
+struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root, u64 parent,
+					u64 root_objectid,
 					struct btrfs_disk_key *key, int level,
 					u64 hint, u64 empty_size);
 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,