!2900 Add initial openeuler_defconfig for arm64 and x86

Merge Pull Request from: @zhengzengkai 
 
If new options are introduced, but openeuler_defconfig is not explicitly
configured, the actual compiled version may be configured according to
the default settings, which may be different from the author's expectation.
Therefore, some commands/scripts are added to help developers to check and update
the defconfig. It is also convenient for continuous integration tools to
check the consistency of defconfig.

Based on OLK-5.10 openeuler_defconfig, use the commands mentioned above to
generate the initial openeuler_defconfig for OLK-6.6 kernel build.

Build and boot testing passed. 
 
Link:https://gitee.com/openeuler/kernel/pulls/2900

 

Reviewed-by: Liu Chao <liuchao173@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>