iwmbt_get_fwname_tlv
extern char *iwmbt_get_fwname_tlv(struct iwmbt_version_tlv *ver,
firmware_path = iwmbt_get_fwname_tlv(&vt, firmware_dir, "sfi");
firmware_path = iwmbt_get_fwname_tlv(&vt, firmware_dir, "ddc");