P31XX: add an init.d script to load the keyboard dock driver

This script can be enabled if needed. Turn it off by default
because the software keyboard won't pop up if the driver got
loaded.

Change-Id: I5a6843370f19744ba61a482cf849c9bd67e766b0
Open source Samsung dock keyboard attach program

Change-Id: I0c29b98f297b8cf8787db455d1ed703b89945592