crypto: sahara - avoid needlessly saving and restoring sahara_ctx

Based on commit 434b421241f2d0 ("crypto: caam - avoid needlessly saving and
restoring caam_hash_ctx") from Russell King.

When exporting and importing the hash state, we will only export and
import into hashes which share the same struct crypto_ahash pointer.
(See hash_accept->af_alg_accept->hash_accept_parent.)

This means that saving the sahara_ctx structure on export, and
restoring it on import is a waste of resources.  So, remove this code.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/sahara.c

@@ -1162,26 +1162,18 @@ static int sahara_sha_digest(struct ahash_request *req)
 
 static int sahara_sha_export(struct ahash_request *req, void *out)
 {
-	struct crypto_ahash *ahash = crypto_ahash_reqtfm(req);
-	struct sahara_ctx *ctx = crypto_ahash_ctx(ahash);
 	struct sahara_sha_reqctx *rctx = ahash_request_ctx(req);
 
-	memcpy(out, ctx, sizeof(struct sahara_ctx));
-	memcpy(out + sizeof(struct sahara_sha_reqctx), rctx,
-	       sizeof(struct sahara_sha_reqctx));
+	memcpy(out, rctx, sizeof(struct sahara_sha_reqctx));
 
 	return 0;
 }
 
 static int sahara_sha_import(struct ahash_request *req, const void *in)
 {
-	struct crypto_ahash *ahash = crypto_ahash_reqtfm(req);
-	struct sahara_ctx *ctx = crypto_ahash_ctx(ahash);
 	struct sahara_sha_reqctx *rctx = ahash_request_ctx(req);
 
-	memcpy(ctx, in, sizeof(struct sahara_ctx));
-	memcpy(rctx, in + sizeof(struct sahara_sha_reqctx),
-	       sizeof(struct sahara_sha_reqctx));
+	memcpy(rctx, in, sizeof(struct sahara_sha_reqctx));
 
 	return 0;
 }