crypto: qat - Add DH support

Add DH support under kpp api. Drop struct qat_rsa_request and
introduce a more generic struct qat_asym_request and share it
between RSA and DH requests.

Signed-off-by: Salvatore Benedetto <salvatore.benedetto@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/qat/Kconfig

@@ -4,6 +4,7 @@ config CRYPTO_DEV_QAT
 	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AKCIPHER
+	select CRYPTO_DH
 	select CRYPTO_HMAC
 	select CRYPTO_RSA
 	select CRYPTO_SHA1