[llvm] [AVR] Temp fix for getPostIndexedAddressParts() (PR #145040)

[Tom Vijlbrief via llvm-commits]

tomtor wrote:

> Doesn't seem so, it's just a post-indexing thingie.

Ok, I think you should take ownership of the fix commit. Not sure what the easiest way to do that is. This PR could just be the new CI test?

Anyway, nice find. I looked briefly at the arm32 sources, but that did not result in anything usefull. :/

https://github.com/llvm/llvm-project/pull/145040