Fix compilation errors in libcudf(rapidsai#7138)

After recent changes in libcudf compilation in rapidsai#7105, the compilation of libcudf on my local machine is broken and these changes fixed the compilation errors.

Authors:
  - galipremsagar <sagarprem75@gmail.com>

Approvers:
  - Keith Kraus (@kkraus14)
  - Devavret Makkar (@devavret)
  - David (@davidwendt)

URL: rapidsai#7138

cpp/src/aggregation/result_cache.cpp

@@ -54,7 +54,7 @@ std::unique_ptr<column> result_cache::release_result(size_t col_idx, aggregation
   auto result_it                 = _cache[col_idx].find(agg);
   std::unique_ptr<column> result = std::move(result_it->second.second);
   _cache[col_idx].erase(result_it);
-  return std::move(result);
+  return result;
 }
 
 }  // namespace detail

cpp/src/comms/ipc/ipc.cpp

@@ -10,7 +10,7 @@ arrow::Result<std::unique_ptr<arrow::ipc::Message>> CudaMessageReader::ReadNextM
   if (host_schema_reader_ != nullptr) {
     auto message        = arrow::ipc::ReadMessage(host_schema_reader_);
     host_schema_reader_ = nullptr;
-    if (message.ok() && *message != nullptr) { return std::move(message); }
+    if (message.ok() && *message != nullptr) { return message; }
   }
   return std::move(arrow::ipc::ReadMessage(stream_, arrow::default_memory_pool()));
 }