[CIPSEC] PSK handshake with PSK larger than 48 bytes is not possible

A PSK handshake with Secret key larger than 48 bytes will be rejected by the Adapter. The reason is a limitation in the mbedTLS library which sets the PSK length per default to 384 bits or 48 bytes.

According to the EtherNet/IP specification vol8. (Edition 1.18) section 5-4.4.5 Pre-Shared Keys – Attribute 5, PSKs must be supported up to 64 bytes.

The device must support arbitrary PSK Identities up to 128 characters in length, and arbitrary PSKs up to 64 octets in length.

The issue is fixed in the mbedTLS library and no changes in the core is required.