[llvm] [AArch64][SME] Remove unused ZA lazy-save (PR #81648)

[Sander de Smalen via llvm-commits]

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@@ -35,6 +35,11 @@ struct AArch64FunctionInfo;
 class AArch64Subtarget;
 class MachineInstr;
 
+struct TPIDR2Object {
+  uint64_t Addr = 0;
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sdesmalen-arm wrote:

```suggestion
  unsigned FI = 0;
```
At this point it is a frame-index, not an address (which couldn't be represented in a compile-time `uint64_t` anyway), so better to just name it as such. Also make it `unsigned` because that's the type used for frame indices.

https://github.com/llvm/llvm-project/pull/81648