cgroup: Use cgroup_attach_{lock,unlock}() from cgroup_attach_task_all()

mainline inclusion
from mainline-v6.1-rc1
commit 075b593f
category: cleanup
bugzilla: 189018, https://gitee.com/openeuler/kernel/issues/I7RPDX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=075b593f54f0f3883532cb750081cae6917bc8fe



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No behavior changes; preparing for potential locking changes in future.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>