fixing uninitialized access

Author: fschlimb

mlir/include/mlir/Dialect/Mesh/IR/MeshOps.h

@@ -44,7 +44,7 @@ class MeshSharding {
   ::mlir::FlatSymbolRefAttr mesh;
   SmallVector<MeshAxesAttr> split_axes;
   SmallVector<MeshAxis> partial_axes;
-  ReductionKind partial_type;
+  ReductionKind partial_type = ReductionKind::Sum;
   SmallVector<int64_t> static_halo_sizes;
   SmallVector<int64_t> static_sharded_dims_offsets;
   SmallVector<Value> dynamic_halo_sizes;