[llvm] [AMDGPU] Ensure non-reserved CSR spilled regs are live-in (PR #146427)

[Matt Arsenault via llvm-commits]

================
@@ -995,6 +996,12 @@ void SIFrameLowering::emitCSRSpillStores(
         }
       };
 
+  for (const Register &Reg : make_first_range(WWMScratchRegs)) {
----------------
arsenm wrote:

```suggestion
  for (const Register Reg : make_first_range(WWMScratchRegs)) {
```

https://github.com/llvm/llvm-project/pull/146427