[Triton-MLIR][BACKEND] Make mmav1 works on basic cases (#944)

TODO:

- Add more cases
- Currently, we just set vec to 4 to make the basic cases pass

Issue:

- the vec in shared layout is different compared to master branch
- when vec=1, it encounters CUDA misalignment error, it doesn't work in
master branch as well
- when setting vec to the value identical to master branch, the MMA
works

lib/Dialect/TritonGPU/Transforms/Combine.cpp

@@ -756,6 +756,7 @@ public:
     auto mod = op->getParentOfType<mlir::ModuleOp>();
     int numWarps = triton::gpu::TritonGPUDialect::getNumWarps(mod);
     int version = computeCapabilityToMMAVersion(computeCapability);
+
     auto newRetType = RankedTensorType::get(
         retShape, oldRetType.getElementType(),
         triton::gpu::MmaEncodingAttr::get(