sepolicy: fix support for lmkd

Allow lmkd to access /dev/memcg once again.

Test: lmkd can access memcg
bug: 36588803
Change-Id: I1f46b438050d95cebd2fcc495938192305fc9fc9

private/file_contexts

@@ -76,6 +76,7 @@
 /dev/cam		u:object_r:camera_device:s0
 /dev/console		u:object_r:console_device:s0
 /dev/cpuctl(/.*)?	u:object_r:cpuctl_device:s0
+/dev/memcg(/.*)?        u:object_r:cgroup:s0
 /dev/device-mapper	u:object_r:dm_device:s0
 /dev/eac		u:object_r:audio_device:s0
 /dev/event-log-tags     u:object_r:runtime_event_log_tags_file:s0