ANDROID: cgroup: Add vendor hook for cpuset.

This hook allows us to capture information when a process is forked so
that we can stat and set some key task's CPU affinity in the ko module
later. This patch, along with aosp/2548175, is necessary for our
affinity settings.

Bug: 183674818
Signed-off-by: lijianzhong <lijianzhong@xiaomi.com>
Change-Id: Ib93e05e5f6c338c5f7ada56bfebdd705f87f1f66
(cherry picked from commit a1883616)