[llvm] [PAC][MC][AArch64] Fix error message for AUTH_ABS64 reloc with ILP32 (PR #89563)

[Daniil Kovalev via llvm-commits]

kovdan01 wrote:

`AArch64ELFObjectWriter::getRelocType` contains many else's after return. If nobody minds, I'll submit a subsequent PR removing use of else after return in this function.

https://github.com/llvm/llvm-project/pull/89563