libtomcrypt: the len parameter of hash.final() is the max size

To be consistent with the behavior of crypto_ops.mac.final(), do not fail if
the length passed to crypto_ops.hash.final() is larger than the hash size.

Also, use TEE_MAX_HASH_SIZE instead of defining another macro (MAX_DIGEST).

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
TEE_DeriveKey(): remove redundant parameter check

paramCount and params are checked by the system service
tee_svc_cryp_derive_key() so they do not need to be checked in libutee.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>