cgroup: minor updates around cgroup_clear_directory()
cgroup: minor updates around cgroup_clear_directory()

* Rename it to cgroup_clear_dir() and make it take the pointer to the
  target cgroup instead of the the dentry.  This makes the function
  consistent with its counterpart - cgroup_populate_dir().

* Move cgroup_clear_directory() invocation from cgroup_d_remove_dir()
  to cgroup_remount() so that the function doesn't have to determine
  the cgroup pointer back from the dentry.  cgroup_d_remove_dir() now
  only deals with vfs, which is slightly cleaner.

This patch doesn't introduce any functional differences.

Signed-off-by: Tejun Heo <546b05909706652891a87f7bfe385ae147f61f91@kernel.org>
Acked-by: Li Zefan <a8167b9d27aca9c6624754deb52c4c6420eded04@huawei.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs