libcgroup: upgrade 2.0 -> 2.0.1

libcgroup: upgrade 2.0 -> 2.0.1

module.patch
musl-decls-compat.patch
removed since they're included in 2.0.1

Changelog:
==========
- Allow reading/writing from cgroup.* files in cgroup v2
- Add support for cgroup v2's cgroup.threads file
- Fix issue where libcgroup/pam wasn't working properly when
  cgrulesengd is disabled
- Fix a bug where the cgroup version wasn't initialized in a
  named cgroup v1 hierarchy
- Various automake bug fixes
- Build PAM module as unversioned DSO
- Fix build issues with musl libc
- Fix potential TOCTOU race in cgroup_get_procs()

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>