[clang] [llvm] [AVR] Fix Avr indvar detection and strength reduction (missed optimization) (PR #152028)

[Tom Vijlbrief via llvm-commits]

tomtor wrote:

We get a build error with lld @benshi001
The windows build went fine.

I think I have to add a .cpp definition

https://github.com/llvm/llvm-project/pull/152028