Set mmap_rnd_bits to 16.

Support for using a greater amount of entropy has been enabled by
means of /proc/sys/kernel/mmap_rnd_bits on arm devices.  Set the
entropy to the maximum value.

Bug: 24047224
Change-Id: I2ffac40634d3d6c253bb800ac5c02a6b937901bf
diff --git a/init.shamu.rc b/init.shamu.rc
index a1bece6..e3f8ef2 100644
--- a/init.shamu.rc
+++ b/init.shamu.rc
@@ -37,6 +37,9 @@
     symlink /sdcard /mnt/sdcard
     symlink /sdcard /storage/sdcard0
 
+    # boost mmap ASLR from 8 to 16 bits
+    write /proc/sys/kernel/mmap_rnd_bits 16
+
 on fs
     mount_all fstab.shamu