[mlir] Address compiler warning

mlir/lib/ExecutionEngine/SparseTensorUtils.cpp

@@ -914,6 +914,7 @@ public:
       : dimSizes(dimSizes), dimTypes(sparsity), nnz(getRank()) {
     assert(dimSizes.size() == dimTypes.size() && "Rank mismatch");
     bool uncompressed = true;
+    (void)uncompressed;
     uint64_t sz = 1; // the product of all `dimSizes` strictly less than `r`.
     for (uint64_t rank = getRank(), r = 0; r < rank; r++) {
       switch (dimTypes[r]) {