cgroup: Return ERSCH when add Z process into task

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8QLND


CVE: NA

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When echo a Z process into tasks, it should return -ERSCH instead of 0.

Signed-off-by: Lu Jialin <lujialin4@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: chenridong <chenridong@huawei.com>