[PATCH 0/4] MR6746: d3dx9: Introduce d3dx_pixel_format_id enumeration.

[Connor McAdams (＠cmcadams)]

This MR contains a set of patches that move away from using `D3DFORMAT` inside of `struct d3dx_image`. This will allow us to support formats that do not have a direct mapping to `D3DFORMAT`, and eventually once we share code with d3dx10/d3dx11 formats that do not have a direct mapping to `DXGI_FORMAT`.

I've pushed a branch [here](https://gitlab.winehq.org/cmcadams/wine/-/tree/UPSTREAM/d3dx9-new-fmt-id-v1?...) containing patches that actually use this new internal format system in practice. I would've included those in this MR, but that seemed like it'd make for a rather large MR. Hopefully splitting it this way makes it easier to review. :)