ChangeLog.d/configuration-split.txt

Changes
   * Cryptography and platform configuration options have been migrated
     from the Mbed TLS library configuration file mbedtls_config.h to
     crypto_config.h that will become the TF-PSA-Crypto configuration file,
     see config-split.md for more information. The reference and test custom
     configuration files respectively in configs/ and tests/configs/ have
     been updated accordingly.
     To migrate custom Mbed TLS configurations where
     MBEDTLS_PSA_CRYPTO_CONFIG is disabled, you should first adapt them
     to the PSA configuration scheme based on PSA_WANT_XXX symbols
     (see psa-conditional-inclusion-c.md for more information).
     To migrate custom Mbed TLS configurations where
     MBEDTLS_PSA_CRYPTO_CONFIG is enabled, you should migrate the
     cryptographic and platform configuration options from mbedtls_config.h
     to crypto_config.h (see config-split.md for more information and configs/
     for examples).