crypto: hisilicon/hpre - add 'ECDH' algorithm

1. Enable 'ECDH' algorithm in Kunpeng 930;
2. HPRE ECDH Support: ecdh-nist-p192, ecdh-nist-p256.

Signed-off-by: Meng Yu <yumeng18@huawei.com>
Reviewed-by: Zaibo Xu <xuzaibo@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>