crypto: virtio - Remove prepare/unprepare request

The callbacks for prepare and unprepare request in crypto_engine
is superfluous.  They can be done directly from do_one_request.

Move the code into do_one_request and remove the unused callbacks.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/virtio/virtio_crypto_akcipher_algs.c

@@ -476,8 +476,6 @@ static int virtio_crypto_rsa_init_tfm(struct crypto_akcipher *tfm)
 
 	ctx->tfm = tfm;
 	ctx->enginectx.op.do_one_request = virtio_crypto_rsa_do_req;
-	ctx->enginectx.op.prepare_request = NULL;
-	ctx->enginectx.op.unprepare_request = NULL;
 
 	akcipher_set_reqsize(tfm,
 			     sizeof(struct virtio_crypto_akcipher_request));

drivers/crypto/virtio/virtio_crypto_skcipher_algs.c

@@ -524,8 +524,6 @@ static int virtio_crypto_skcipher_init(struct crypto_skcipher *tfm)
 	ctx->tfm = tfm;
 
 	ctx->enginectx.op.do_one_request = virtio_crypto_skcipher_crypt_req;
-	ctx->enginectx.op.prepare_request = NULL;
-	ctx->enginectx.op.unprepare_request = NULL;
 	return 0;
 }