crypto: akcipher - Support more than one signature encoding

Currently only a single default signature encoding is supported per
akcipher.

A subsequent commit will allow a second encoding for ecdsa, namely P1363
alternatively to X9.62.

To accommodate for that, amend struct akcipher_request and struct
crypto_akcipher_sync_data to store the desired signature encoding for
verify and sign ops.

Amend akcipher_request_set_crypt(), crypto_sig_verify() and
crypto_sig_sign() with an additional parameter which specifies the
desired signature encoding.  Adjust all callers.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
9 files changed