This allows Phase 2 Identity Request to be skipped if the identity is
already known from PAC-Opaque received in TLS handshake in order to save
one roundtrip from normal authentication.
This allows associations to be denied if the STA tries to use too large
listen interval. The default value is 65535 which matches with the field
size limits.
These are expected in most cases and there is no need to confuse users
with the messages in stderr (perror was used here). These are now only
shown in debug output and EOPNOTSUPP errors are silently ignored.
