fix histogram kernel format; test=develop

paddle/pten/kernels/histogram_kernel.h

-
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 
 #pragma once
 
@@ -7,10 +19,10 @@ namespace pten {
 
 template <typename T, typename Context>
 void HistogramSelectKernel(const Context& dev_ctx,
-                        const DenseTensor& input,
-                        int64_t bins,
-                        int min,
-                        int max,
-                        DenseTensor* out);
+                           const DenseTensor& input,
+                           int64_t bins,
+                           int min,
+                           int max,
+                           DenseTensor* out);
 
-}  // namspace pten
+}  // namespace pten