[clang] [llvm] [AVR] Add support for many new AVR MCUs (PR #143914)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

@tomtor @benshi001 @Patryk27 I've landed 62d8e001dac4b1a68f5b33c8784adba1335003f4 to revert this PR.  I'm getting:

```
llvm/lib/Target/AVR/AVRDevices.td:591:27: error: Variable not defined: 'FamilyXMEGA2'
def : Device<"avr64da28", FamilyXMEGA2, ELFArchXMEGA2>;
                          ^
```

I'm happy to try your revised patch.  Thanks!


https://github.com/llvm/llvm-project/pull/143914