x86 / config: add openeuler_defconfig

hulk inclusion
category: config
bugzilla: 31089
CVE: NA

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Add openeuler_defconfig for openeuler itself.
Signed-off-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-By: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>