GPU: The D3D12 blit shaders are DXIL

(cherry picked from commit 205c34c62a)

src/gpu/d3d12/SDL_gpu_d3d12.c

@@ -8102,7 +8102,7 @@ static void D3D12_INTERNAL_InitBlitResources(
     shaderCreateInfo.code = (Uint8 *)D3D12_FullscreenVert;
     shaderCreateInfo.code_size = sizeof(D3D12_FullscreenVert);
     shaderCreateInfo.stage = SDL_GPU_SHADERSTAGE_VERTEX;
-    shaderCreateInfo.format = SDL_GPU_SHADERFORMAT_DXBC;
+    shaderCreateInfo.format = SDL_GPU_SHADERFORMAT_DXIL;
 
     renderer->blitVertexShader = D3D12_CreateShader(
         (SDL_GPURenderer *)renderer,