crypto: xts - 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/xts.c

@@ -338,9 +338,9 @@ static void xts_free_instance(struct skcipher_instance *inst)
 
 static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
 {
+	struct skcipher_alg_common *alg;
 	struct skcipher_instance *inst;
 	struct xts_instance_ctx *ctx;
-	struct skcipher_alg *alg;
 	const char *cipher_name;
 	u32 mask;
 	int err;
@@ -375,13 +375,13 @@ static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
 	if (err)
 		goto err_free_inst;
 
-	alg = crypto_skcipher_spawn_alg(&ctx->spawn);
+	alg = crypto_spawn_skcipher_alg_common(&ctx->spawn);
 
 	err = -EINVAL;
 	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
 		goto err_free_inst;
 
-	if (crypto_skcipher_alg_ivsize(alg))
+	if (alg->ivsize)
 		goto err_free_inst;
 
 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
@@ -421,8 +421,8 @@ static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
 				       (__alignof__(u64) - 1);
 
 	inst->alg.ivsize = XTS_BLOCK_SIZE;
-	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
-	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
+	inst->alg.min_keysize = alg->min_keysize * 2;
+	inst->alg.max_keysize = alg->max_keysize * 2;
 
 	inst->alg.base.cra_ctxsize = sizeof(struct xts_tfm_ctx);