rootdir: reduce permissions on /dev/rtc0

Remove world-readable, reduce group permissions to readable by system
daemons

Change-Id: I6c7d7d78b8d8281960659bb8490a01cf7fde28b4
Signed-off-by: Greg Hackmann <ghackmann@google.com>
diff --git a/rootdir/ueventd.rc b/rootdir/ueventd.rc
index 9bf17e2..b8fe716 100644
--- a/rootdir/ueventd.rc
+++ b/rootdir/ueventd.rc
@@ -35,7 +35,7 @@
 /dev/uhid                 0660   system     net_bt_stack
 /dev/uinput               0660   system     net_bt_stack
 /dev/alarm                0664   system     radio
-/dev/rtc0                 0664   system     radio
+/dev/rtc0                 0640   system     system
 /dev/tty0                 0660   root       system
 /dev/graphics/*           0660   root       graphics
 /dev/msm_hw3dm            0660   system     graphics