include: Fix a typo in IDirect3D9Ex method

[Henri Verbeet]

On 22 May 2016 at 14:30, Andrey Gusev <andrey.goosev at gmail.com> wrote:
> -    STDMETHOD(GetAdapterLUID)(THIS_ UINT Adatper, LUID *pLUID) PURE;
> +    STDMETHOD(GetAdapterLUID)(THIS_ UINT Adapter, LUID *pLUID) PURE;
If you're touching it anyway, "Adapter" => "adapter" and "pLUID" => "luid".