wined3d: Avoid crashing when ProcessVertices is called with NULL vertex declaration

[H. Verbeet]

On 04/09/06, Paul Chitescu <pchitescu at voip.null.ro> wrote:
> Changelog: Avoid a segfault in IWineD3DDeviceImpl_ProcessVertices by checking
> if SrcImpl (parameter pVertexDecl) is NULL.
>
> The function is called from dlls/d3d8/device.c
> IDirect3DDevice8Impl_ProcessVertices with an explicit NULL as vertex
> declaration parameter.
>
> Crash was observed in Age of Mythology Trial.
>
This doesn't look correct to me, the call does effectively nothing for d3d8 now.