Allowing system_server to search sysfs_power dir

rw access to sysfs_power file is not enough; in some cases search access
is also needed

Bug: 67895406
Test: system_server can access memory power statistics
Change-Id: I471e8e60626e6eed35e74e25a0f4be470885a459

private/system_server.te

@@ -287,6 +287,7 @@ r_dir_file(system_server, sysfs_wakeup_reasons)
 allow system_server sysfs_nfc_power_writable:file rw_file_perms;
 allow system_server sysfs_devices_system_cpu:file w_file_perms;
 allow system_server sysfs_mac_address:file r_file_perms;
+allow system_server sysfs_power:dir search;
 allow system_server sysfs_power:file rw_file_perms;
 allow system_server sysfs_thermal:dir search;
 allow system_server sysfs_thermal:file r_file_perms;