wined3d: Add Nvidia 8800GTX detection

[Chris Robinson]

On Tuesday, July 20, 2010 2:54:24 pm Luke Bratch wrote:
> The attached uses that experimental extension [1] to report the correct
> total memory for cards that support it, while sticking with the existing
> hard coded values and code layout for those that don't.

I think the extension should be checked regardless of the card type. 
Especially with the open source drivers, there's no reason ATi or Intel cards 
can't pick it up. And with the Nouveau driver, even older nVidia cards can get 
it.

I'd also think the wrapping function should be generically named, so it can be 
extended to use other extensions, in case alternative ones come up.

On a technical note, it looks like you're checking the extension incorrectly. 
You're checking the address of the extension array entry, instead of the array 
entry value.