[clang] [clang] fix uefi target for aarch64 & x86_64 (PR #120632)

[Tristan Ross via cfe-commits]

RossComputerGuy wrote:

We have a problem where everything related to `i128` / `long double` fail to compile in LLVM libc without compiler-rt on aarch64 and possibly x86_64, this is a problem. Related ABI info:
- [aarch64](https://github.com/ARM-software/abi-aa/releases/download/2024Q3/aapcs64.pdf)
- [UEFI 2.10](https://uefi.org/sites/default/files/resources/UEFI_Spec_2_10_Aug29.pdf) - 2.3.6.4

We probably should fix that in this PR.

https://github.com/llvm/llvm-project/pull/120632