wined3d: universal surface convertor function for unsigned integer color formats(5th attempt)

[Stefan Dösinger]

> Well, the last attempt (with added big-endian support) was submitted
several 
> days ago, and again - no feedback, and patch still isn't accepted.

> What's wrong with patch now?
Sorry, I must have missed this on Wine-patches again :-(

It look ok to me. The endianess #ifdefs look strange, but I don't know how
that's supposed to be handled.

PS: Sorry, I lost the original mail. I don't know how to supply a reference
ID to outlook, so I broke the thread appart