crypto: n2 - Set err to EINVAL if snprintf fails for hmac

Return EINVAL if the snprintf check fails when constructing the
algorithm names.

Fixes: 8c20982c ("crypto: n2 - Silence gcc format-truncation false positive warnings")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202409090726.TP0WfY7p-lkp@intel.com/Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/n2_core.c

@@ -1353,6 +1353,7 @@ static int __n2_register_one_hmac(struct n2_ahash_alg *n2ahash)
 	ahash->setkey = n2_hmac_async_setkey;
 
 	base = &ahash->halg.base;
+	err = -EINVAL;
 	if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)",
 		     p->child_alg) >= CRYPTO_MAX_ALG_NAME)
 		goto out_free_p;