config: add initial openeuler_defconfig for sw64

Sunway inclusion
category: config
bugzilla: https://gitee.com/openeuler/kernel/issues/I56OSP



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Add initial openeuler_defconfig for SW64 platform.

Signed-off-by: Gu Zitao <guzitao@wxiat.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>