dinput: Convert keyboard buffer from internal data format to user data format

[Sergey Khodych]

A possibility of using custom data format, for any type of devices, is
described in DirectX SDK documentation.
For example Monolith's  F.E.A.R. use this method.

> Any particular reason for this? Do you have a program that sets different 
> data format? The reason I ask - copying 256 bytes is much faster then 
> iterating over the whole data format and copying one byte at a time.
> 
> Vitaliy.
> 
> 
>