[llvm] [PEI][PowerPC] Fix false alarm of stack size limit (PR #65559)

[via llvm-commits]

bzEq wrote:

> Were we always getting this warning on the tests added in https://github.com/llvm/llvm-project/commit/5018a5dcbe70a9e2e39341762ec0ca0ad76d28b4?

I think so, I didn't catch that in `FileCheck`. For current llc run on `huge-frame-size.ll`.
```
warning: <unknown>:0:0: stack frame size (4294967344) exceeds limit (4294967295) in function 'foo'
```

https://github.com/llvm/llvm-project/pull/65559