Remove use of CyaSSL_Mutex in wolfcrypt

[aburks]

There are a few vestigial uses of CyaSSL_Mutex in wolfcrypt:

AES: https://github.com/wolfSSL/wolfssl/blob/master/wolfcrypt/src/aes.c#L1438
ECC: https://github.com/wolfSSL/wolfssl/blob/master/wolfcrypt/src/ecc.c#L2653

[toddouska]

Thanks! Good finds.