[clang] [Clang][AArch64] Add fp8 variants for untyped NEON intrinsics (PR #128019)

[via cfe-commits]

Lukacma wrote:

@paulwalker-arm the reasoning behind creating separate records, is that mfloat type is not available for aarch32 architectures and therefore all intrinsics using it need to be gated behind `ArchGuard = "defined(__aarch64__)"` .

https://github.com/llvm/llvm-project/pull/128019