[Ltib] Proper Addition of Device Node

[Lysle Shields]

What is the proper way to make a specific platform create a device node in
the root filesystem.  Editing ltib/bin/device_table.txt will affect everyone
when really only one platform needs to have that device node.

Suggestions?

(For now, I'm telling people to edit device_table.txt after running LTIB for
the first time)

Thanks,
Lysle Shields