statsd: Give statsd permission to access PowerStats HAL

PowerStats HAL has been recently added. Giving statsd permission to
access it.

Bug: 120551881
Test: make selinux_policy
Test: adb shell cmd stats pull-source 10005
Change-Id: I23cb915886c205b034199e63c8fc735ef32f61f6

public/statsd.te

@@ -60,6 +60,7 @@ allow statsd dumpstate:fifo_file { getattr write };
 allow statsd proc_uid_cputime_showstat:file { getattr open read };
 hal_client_domain(statsd, hal_health)
 hal_client_domain(statsd, hal_power)
+hal_client_domain(statsd, hal_power_stats)
 hal_client_domain(statsd, hal_thermal)
 
 # Allow 'adb shell cmd' to upload configs and download output.