[clang] [llvm] [AArch64] Add -mlr-for-calls-only to replace the now removed -ffixed-x30 flag. (PR #98073)

[Amara Emerson via cfe-commits]

aemerson wrote:

Thanks, the live-in flag seems to be added correctly for the return in the new test.

https://github.com/llvm/llvm-project/pull/98073