Remove redundant NIST_KW checks in cipher_auth_xxcrypt()
Remove redundant NIST_KW checks in cipher_auth_xxcrypt()

The internal functions mbedtls_cipher_aead_{encrypt,decrypt} reject
unsupported algorithms, so there's no need for an additional check in
the legacy wrappers.

Signed-off-by: Gilles Peskine <f805f64266d288fc5467baa7be6cd0ff366f477b@arm.com>

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