sepolicy: rename proc.uidcpupower to sys.uidcpupower

Rename proc.uidcpupower to sys.uidcpupower so system server can
read and set the property

Test: adb shell settings put global sys_uidcpupower 1
      verify via getprop sys.uidcpupower
diff --git a/init.common.rc b/init.common.rc
index dfa92db..b7eda71 100644
--- a/init.common.rc
+++ b/init.common.rc
@@ -560,10 +560,10 @@
 on property:init.svc.per_mgr=running
     start per_proxy
 
-on property:proc.uidcpupower=*
+on property:sys.uidcpupower=*
    write /proc/uid_cpupower/enable 1
 
-on property:proc.uidcpupower=0
+on property:sys.uidcpupower=0
    write /proc/uid_cpupower/enable 0
 
 on property:sys.shutdown.requested=*