init: Replace cgroup hardcoded path with detected one

Remove hardcoded cpuset path usage and replace it with a request to
get the path using new API.

Exempt-From-Owner-Approval: already approved in internal master

Bug: 111307099
Test: builds, boots

Change-Id: I211d093c24a682e2d1992c08e4c1d980379711a4
Merged-In: I211d093c24a682e2d1992c08e4c1d980379711a4
Signed-off-by: Suren Baghdasaryan <surenb@google.com>