Revert "[lld][AArch64][ELF][PAC] Support `.relr.auth.dyn` section" (#94843)

Reverts llvm/llvm-project#87635

On some corner cases, lld generated an object file with an empty REL
section with `sh_info` set to 0. This file triggers an lld error when
used as its input. See
https://github.com/llvm/llvm-project/pull/87635#issuecomment-2155318065
for details.