crypto: ctr - Only access common skcipher fields on spawn

As skcipher spawns may be of the type lskcipher, only the common
fields may be accessed.  This was already the case but use the
correct helpers to make this more obvious.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/ctr.c

@@ -258,8 +258,8 @@ static int crypto_rfc3686_create(struct crypto_template *tmpl,
 				 struct rtattr **tb)
 {
 	struct skcipher_instance *inst;
-	struct skcipher_alg *alg;
 	struct crypto_skcipher_spawn *spawn;
+	struct skcipher_alg_common *alg;
 	u32 mask;
 	int err;
 
@@ -278,11 +278,11 @@ static int crypto_rfc3686_create(struct crypto_template *tmpl,
 	if (err)
 		goto err_free_inst;
 
-	alg = crypto_spawn_skcipher_alg(spawn);
+	alg = crypto_spawn_skcipher_alg_common(spawn);
 
 	/* We only support 16-byte blocks. */
 	err = -EINVAL;
-	if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
+	if (alg->ivsize != CTR_RFC3686_BLOCK_SIZE)
 		goto err_free_inst;
 
 	/* Not a stream cipher? */
@@ -303,11 +303,9 @@ static int crypto_rfc3686_create(struct crypto_template *tmpl,
 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
 
 	inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
-	inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
-	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
-				CTR_RFC3686_NONCE_SIZE;
-	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
-				CTR_RFC3686_NONCE_SIZE;
+	inst->alg.chunksize = alg->chunksize;
+	inst->alg.min_keysize = alg->min_keysize + CTR_RFC3686_NONCE_SIZE;
+	inst->alg.max_keysize = alg->max_keysize + CTR_RFC3686_NONCE_SIZE;
 
 	inst->alg.setkey = crypto_rfc3686_setkey;
 	inst->alg.encrypt = crypto_rfc3686_crypt;