remove unused codes

paddle/framework/detail/tensor-inl.h

@@ -13,7 +13,6 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #pragma once
-#include <string>
 #include "paddle/memory/memcpy.h"
 
 namespace paddle {

paddle/framework/tensor.h

@@ -19,7 +19,6 @@ limitations under the License. */
 #include <memory>
 #include <typeindex>
 #include "paddle/framework/ddim.h"
-#include "paddle/memory/memcpy.h"
 #include "paddle/memory/memory.h"
 #include "paddle/platform/device_context.h"
 #include "paddle/platform/enforce.h"
@@ -110,8 +109,6 @@ class Tensor {
   template <typename T>
   inline void check_memory_size() const;
 
-  paddle::platform::Place place() const { return holder_->place(); }
-
  private:
   /**
    * @note    Placeholder hides type T, so it doesn't appear as a template