For RSA PSS, document that salt length = hash length
For RSA PSS, document that salt length = hash length

This is the most common mode and the only mode that Mbed TLS functions
fully supports (mbedtls_rsa_rsassa_pss_verify_ext can verify
signatures with a different salt length).

NXPmicro/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls