lowmemorykiller: make perms 0220

Set

* /sys/module/lowmemorykiller/parameters/adj
* /sys/module/lowmemorykiller/parameters/minfree

to 0220. This better indicates that these files are only intended
to be written to, never read.

Change-Id: I9ef054f032b3955e04128fc1a472a17c7b1fa792
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 51246fb..8239999 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -303,9 +303,9 @@
     write /proc/sys/vm/overcommit_memory 1
     write /proc/sys/vm/min_free_order_shift 4
     chown root system /sys/module/lowmemorykiller/parameters/adj
-    chmod 0664 /sys/module/lowmemorykiller/parameters/adj
+    chmod 0220 /sys/module/lowmemorykiller/parameters/adj
     chown root system /sys/module/lowmemorykiller/parameters/minfree
-    chmod 0664 /sys/module/lowmemorykiller/parameters/minfree
+    chmod 0220 /sys/module/lowmemorykiller/parameters/minfree
 
     # Tweak background writeout
     write /proc/sys/vm/dirty_expire_centisecs 200