[clang] [CLANG][AArch64]Add Neon vectors for mfloat8_t (PR #99865)

[Kazu Hirata via cfe-commits]

kazutakahirata wrote:

lldb is failing to build with:

```
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:4888:13: error: enumeration values 'MFloat8x8' and 'MFloat8x16' not handled in switch [-Werror,-Wswitch]
    switch (llvm::cast<clang::BuiltinType>(qual_type)->getKind()) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
```

Would you mind taking a look?  Thanks!

https://github.com/llvm/llvm-project/pull/99865