crypto: hisilicon/hpre - delete wrap of 'CONFIG_CRYPTO_DH'

'CRYPTO_DH' has selected in 'Kconfig', so delete 'CONFIG_CRYPTO_DH'.

Signed-off-by: Hui Tang <tanghui20@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>