[clang] [HLSL] fix D3DCOLORtoUBYTE4 return type to be int (PR #151353)

[Deric C. via cfe-commits]

================
@@ -12,7 +12,7 @@
 namespace hlsl {
 namespace __detail {
 
-constexpr vector<uint, 4> d3d_color_to_ubyte4_impl(vector<float, 4> V) {
+constexpr vector<int, 4> d3d_color_to_ubyte4_impl(vector<float, 4> V) {
----------------
Icohedron wrote:

```suggestion
constexpr vector<int, 4> d3d_color_to_ubyte4_impl(float4 V) {
```
Why not use float4 here as well?

https://github.com/llvm/llvm-project/pull/151353