Allow BatterySaver access to cpufreq on wahoo.

Bug: 68988722
Test: n/a
Change-Id: I58b502e0f9741f9374a2c079f8fad674639011e6
diff --git a/sepolicy/vendor/system_server.te b/sepolicy/vendor/system_server.te
index 090cadf..ce34d68 100644
--- a/sepolicy/vendor/system_server.te
+++ b/sepolicy/vendor/system_server.te
@@ -8,6 +8,9 @@
 allow system_server persist_sensors_file:file r_file_perms;
 allow system_server wlan_device:chr_file rw_file_perms;
 
+# BatterySaver access to cpufreq.
+allow system_server sysfs_devices_system_cpu:file w_file_perms;
+
 # input files
 r_dir_file(system_server, idc_file)
 r_dir_file(system_server, keylayout_file)