rootdir: writepid to the correct schedTune cgroup mount point

Seems like AOSP missed these out when switching the schedTune
cgroup mount point from /sys/fs/cgroup/stune/ to /dev/stune/.

Reference commit:
11cde56 Mount schedTune cgroup as /dev/stune

Change-Id: Ie8b1e7f95af6aef82a914199a48e491a00f210b6

Author: zwliew

rootdir/init.zygote32_64.rc

@@ -7,7 +7,7 @@ service zygote /system/bin/app_process32 -Xzygote /system/bin --zygote --start-s
     onrestart restart cameraserver
     onrestart restart media
     onrestart restart netd
-    writepid /dev/cpuset/foreground/tasks /sys/fs/cgroup/stune/foreground/tasks
+    writepid /dev/cpuset/foreground/tasks /dev/stune/foreground/tasks
 
 service zygote_secondary /system/bin/app_process64 -Xzygote /system/bin --zygote --socket-name=zygote_secondary
     class main

rootdir/init.zygote64_32.rc

@@ -7,7 +7,7 @@ service zygote /system/bin/app_process64 -Xzygote /system/bin --zygote --start-s
     onrestart restart cameraserver
     onrestart restart media
     onrestart restart netd
-    writepid /dev/cpuset/foreground/tasks /sys/fs/cgroup/stune/foreground/tasks
+    writepid /dev/cpuset/foreground/tasks /dev/stune/foreground/tasks
 
 service zygote_secondary /system/bin/app_process32 -Xzygote /system/bin --zygote --socket-name=zygote_secondary
     class main