d3dx9: Add stubs for the ID3DXRenderToSurface functions [PATCH8/9]

[H. Verbeet]

<tony.wasserka at freenet.de> wrote:
> Thank you very much for pointing that out :)
> Is there anything else wrong with it or can I resend the patches?
A minor issue could be that you're returning S_OK in most of the
stubs. For the IUnknown stuff that's correct, but D3D stuff typically
returns D3D_OK. Although S_OK and D3D_OK have the same value, using
D3D_OK would be a bit more consistent once you start returning eg.
D3DERR_INVALIDCALL on error conditions.