vkd3d-shader/spirv: Emit dp2add.
I noticed that the Plarium logo looked wrong when starting the PlariumPlay launcher in wine with the Vulkan backend. It turned out dp2add was not emitted, so I added it and now the logo looks correct.
I noticed that the Plarium logo looked wrong when starting the PlariumPlay launcher in wine with the Vulkan backend. It turned out dp2add was not emitted, so I added it and now the logo looks correct.