[clang] [llvm] [aarch64][clang][llvm] Allow AArch64 TLB maintenance instructions to be enabled via -march (PR #116707)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic commented:

__ARM_FEATURE_* defines are, as far as I know, supposed to be defined in the ACLE.  So there needs to be an issue/PR for the ACLE spec.  Once Arm reviews that, we can merge the corresponding patches here.

https://github.com/llvm/llvm-project/pull/116707