[ofw] Porting OFA stack to WDK

[Sean Hefty]

>    - remove __ptr64 attribute from all the functions of the stack;
>    - remove __ptr64 attribute from all the structures except the
>	 Ioctl ones;
>    - use PtrToPtr64 function while the assignment of __ptr64 Ioctl
>	 fields (only in user space);
>    - remove unnecessary castings, related to __ptr64 attriubute all
>	 over the code, if any;
 
I think this would require that apps re-compile, but...

I also don't think __ptr64 should be in any user interface functions or
structures.

Do we know if apps would need to recompile?  And, if so, are we okay with that?
Do we want to consider this change for a 2.0 release?

- Sean