[llvm] [mlir] [mlir][ArmNeon] Implements LowerVectorToArmNeon Pattern for SMMLA (PR #81895)

[Kojo Acquah via llvm-commits]

KoolJBlack wrote:

It looks like the `******************** TEST 'MLIR :: python/dialects/arith_dialect.py' FAILED ********************` test is failing with:
```
ValueError: DenseElementsAttr could not be constructed from the given buffer. This may mean that the Python buffer layout does not match that MLIR expected layout and is a bug.
```

I'm not sure how this relates to this PR. Its only the windows runner. Perhaps an unrelated issue? @dcaballe 

https://github.com/llvm/llvm-project/pull/81895