UDF volume is only mounted with UDF_FLAG_UTF8
or UDF_FLAG_NLS_MAP (see fill udf_fill_super().
BUG() if we have something different in udf_get_filename()
Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Jan Kara <jack@suse.cz>