[NFC][ELF][AArch64][PAC] Use existing addSymbolReloc for R_AARCH64_AUTH_ABS64
The only difference between these calls is whether rel or type is passed
as the first argument, but AArch64::getDynRel returns type unchanged for
R_AARCH64_AUTH_ABS64, so they are the same.
Reviewers: MaskRay, kovdan01
Pull Request: https://github.com/llvm/llvm-project/pull/171179