x86 / config: add openeuler_defconfig

hulk inclusion
category: config
bugzilla: 31089
CVE: NA

-----------------------------

Add openeuler_defconfig for openeuler itself.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-By: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>