NLA: init: create camera-daemon stune cgroup

Create an stune cgroup for the camera-daemon
so it can be tuned independently of top-app
or foreground.

Bug: 136608042
Test: boot and look at camera traces with different
      stune settings

Change-Id: I2c59ff237508dacf66f632e1334599b44222ab69

rootdir/etc/init.target.rc

@@ -246,6 +246,14 @@ on boot
     chown cameraserver cameraserver /dev/cpuset/camera-daemon
     chown cameraserver cameraserver /dev/cpuset/camera-daemon/tasks
     chmod 0660 /dev/cpuset/camera-daemon/tasks
+
+    # create an stune group for camera-specific processes
+    mkdir /dev/stune/camera-daemon
+    write /dev/stune/camera-daemon/schedtune.prefer_idle 1
+    write /dev/stune/camera-daemon/schedtune.boost 0
+    chown system system /dev/stune/camera-daemon
+    chown system system /dev/stune/camera-daemon/tasks
+    chmod 0664 /dev/stune/camera-daemon/tasks
 
     # Set fingerprint device permissions
     chown system system /dev/goodix_fp