[CRYPTO] cryptd: Correct kzalloc error test

Normally, kzalloc returns NULL or a valid pointer value, not a value to be
tested using IS_ERR.
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/cryptd.c

@@ -190,8 +190,10 @@ static struct crypto_instance *cryptd_alloc_instance(struct crypto_alg *alg,
 	int err;
 
 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
-	if (IS_ERR(inst))
+	if (!inst) {
+		inst = ERR_PTR(-ENOMEM);
 		goto out;
+	}
 
 	err = -ENAMETOOLONG;
 	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,