msm8953-common: Add system/wakelock groups to post_boot.sh script

The post_boot script writes to scaling_(min/max)_feq and
wake_lock nodes which are owned by system and wakelock groups.

Change-Id: Ief83a152f8433976082aaa129bdb193dd3adb320

rootdir/init.qcom.rc

@@ -534,6 +534,7 @@ on property:ro.vendor.ril.mbn_copy_completed=1
 service qcom-post-boot /vendor/bin/init.qcom.post_boot.sh
     class late_start
     user root
+    group root system wakelock
     disabled
     oneshot