btrfs: remaining BTRFS_PATH_AUTO_FREE conversions

btrfs: remaining BTRFS_PATH_AUTO_FREE conversions

Do the remaining btrfs_path conversion to the auto cleaning, this seems
to be the last one. Most of the conversions are trivial, only adding the
declaration and removing the freeing, or changing the goto patterns to
return.

There are some functions with many changes, like __btrfs_free_extent(),
btrfs_remove_from_free_space_tree() or btrfs_add_to_free_space_tree()
but it still follows the same pattern.

Signed-off-by: David Sterba <dsterba@suse.com>