sepolicy: rename cgroup_v2 back to cgroup_bpf

The type name change from cgroup_bpf into cgroup_v2 caused
http://b/166064067. Rename back to cgroup_bpf.

Bug: 166064067
Test: compiled and booted on a sunfish. Manually tested network and app
freezer

Change-Id: Ib39eb104e73d6dca3b1f61b108a3deeea31ff880
Merged-In: Idfb3f6e77b60dad032d1e306d2f9b58cd5775960
14 files changed