selftests: tls: add missing AES256-GCM cipher

Add tests for TLSv1.2 and TLSv1.3 with AES256-GCM cipher

Signed-off-by: Vadim Fedorenko <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/net/tls.c

···
 		struct tls12_crypto_info_sm4_gcm sm4gcm;
 		struct tls12_crypto_info_sm4_ccm sm4ccm;
 		struct tls12_crypto_info_aes_ccm_128 aesccm128;
+		struct tls12_crypto_info_aes_gcm_256 aesgcm256;
 	};
 	size_t len;
 };
···
 		tls12->len = sizeof(struct tls12_crypto_info_aes_ccm_128);
 		tls12->aesccm128.info.version = tls_version;
 		tls12->aesccm128.info.cipher_type = cipher_type;
+		break;
+	case TLS_CIPHER_AES_GCM_256:
+		tls12->len = sizeof(struct tls12_crypto_info_aes_gcm_256);
+		tls12->aesgcm256.info.version = tls_version;
+		tls12->aesgcm256.info.cipher_type = cipher_type;
 		break;
 	default:
 		break;
···
 {
 	.tls_version = TLS_1_3_VERSION,
 	.cipher_type = TLS_CIPHER_AES_CCM_128,
+};
+
+FIXTURE_VARIANT_ADD(tls, 12_aes_gcm_256)
+{
+	.tls_version = TLS_1_2_VERSION,
+	.cipher_type = TLS_CIPHER_AES_GCM_256,
+};
+
+FIXTURE_VARIANT_ADD(tls, 13_aes_gcm_256)
+{
+	.tls_version = TLS_1_3_VERSION,
+	.cipher_type = TLS_CIPHER_AES_GCM_256,
 };
 
 FIXTURE_SETUP(tls)