!1432 kconfig: Add script to check & update openeuler_defconfig

Merge Pull Request from: @ci-robot 
 
PR sync from: Xie XiuQi <xiexiuqi@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/U3P75KYVZKCUP22RDVGBZNWQQO5KL7RV/ 
 
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, the some command is added to help developers to check and update
the defconfig. It is also convenient for continuous integration tools to
check the consistency of defconfig.

Reference: https://gitee.com/openeuler/kernel/issues/I68D0O
Reference: https://gitee.com/openeuler/kernel/issues/I63KVP
Reference: https://gitee.com/openeuler/kernel/pulls/286
Reference: https://gitee.com/openeuler/kernel/commit/ca1af5899ef7c1e1617913ecee37d53972f701fb

```
Usage:
  make check_oedefconfig
  #
  # New options might needs to be updated to the default configuration
  # file. Use the following command:
  # 'make openeuler_defconfig/menuconfig/update_oedefconfig/save_oedefconfig'
  # !!! DO NOT EDIT !!!
  #
  # defconfig: arch/arm64/configs/openeuler_defconfig
  #
  CONFIG_MEMCG=n
  CONFIG_BLK_CGROUP=n
  CONFIG_CFS_BANDWIDTH=n
  CONFIG_RT_GROUP_SCHED=n
  CONFIG_CGROUP_PIDS=n
  CONFIG_CGROUP_RDMA=n
  CONFIG_CGROUP_FREEZER=n
  CONFIG_CGROUP_HUGETLB=n
  CONFIG_CPUSETS=n

  make update_oedefconfig
  # Update openeuler_defconfig base on current source code

  make save_oedefconfig
  # Save current .config to openeuler_defconfig'
```

If someone adds a new Kconfig, he should also explicitly update
openeuler_defconfig, whether it's enabled or disabled.

Again, do *NOT* edit openeuler_defconfig directly.

Link: https://gitee.com/openeuler/kernel/pulls/286 
 
Link:https://gitee.com/openeuler/kernel/pulls/1432

 

Reviewed-by: Liu Chao <liuchao173@huawei.com>
Reviewed-by: Jason Zeng <jason.zeng@intel.com>
Signed-off-by: Wei Li <liwei391@huawei.com>