sepolicy: rules for uid/pid cgroups v2 hierarchy

Bug: 168907513
Test: verified the correct working of the v2 uid/pid hierarchy in normal
and recovery modes

This reverts commit aa8bb3a29b92a342c42c802edac269da5984d1df.

Change-Id: Ib344d500ea49b86e862e223ab58a16601eebef47
diff --git a/private/surfaceflinger.te b/private/surfaceflinger.te
index 37601b9..8549bd5 100644
--- a/private/surfaceflinger.te
+++ b/private/surfaceflinger.te
@@ -100,6 +100,7 @@
 allow surfaceflinger self:global_capability_class_set sys_nice;
 allow surfaceflinger proc_meminfo:file r_file_perms;
 r_dir_file(surfaceflinger, cgroup)
+r_dir_file(surfaceflinger, cgroup_v2)
 r_dir_file(surfaceflinger, system_file)
 allow surfaceflinger tmpfs:dir r_dir_perms;
 allow surfaceflinger system_server:fd use;