[llvm] [GlobalIsel][AArch64] legalize ptr add (PR #89218)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

```
Assertion failed: (llvm::all_of(SrcOps, [&, this](const SrcOp &Op) { return Op.getLLTTy(*getMRI()) == SrcOps[0].getLLTTy(*getMRI()); }) && "type mismatch in input list"), function buildInstr, file MachineIRBuilder.cpp, line 1355.
```

https://github.com/llvm/llvm-project/pull/89218