init: increase read-ahead value to 256 kb

Apps and database file sizes have increased in recent Android versions,
which makes it practical to increase our read-ahead value from 128 kb.

General user experience seem to have improved a bit.

Change-Id: I5d0e367ecdd562599d7f6c93149aa68738987d6d

rootdir/init.smdk4210.rc

@@ -318,6 +318,9 @@ on boot
     setprop status.battery.level_raw  50
     setprop status.battery.level_scale 9
 
+# increase read-ahead value to 256 kb
+    write /sys/block/mmcblk0/queue/read_ahead_kb 256
+
 # For RIL
 service cpboot-daemon /sbin/cbd -d -p 8
     class main