fix code style (#11862)

paddle/fluid/platform/mkldnn_helper.h

@@ -14,6 +14,7 @@ limitations under the License. */
 #pragma once
 
 #include <mkldnn.h>
+#include <string>
 #include <vector>
 #include "paddle/fluid/framework/operator.h"
 #include "paddle/fluid/platform/place.h"
@@ -182,10 +183,11 @@ class MKLDNNHandler {
   }
 
   std::shared_ptr<mkldnn::memory> AcquireMemory(
-      mkldnn::memory::primitive_desc& mpd,
-      mkldnn::memory::primitive_desc& user_mpd,
+      mkldnn::memory::primitive_desc& mpd,       // NOLINT
+      mkldnn::memory::primitive_desc& user_mpd,  // NOLINT
       const std::shared_ptr<mkldnn::memory> user_memory_p,
-      const std::string& suffix, std::vector<mkldnn::primitive>& pipeline) {
+      const std::string& suffix,
+      std::vector<mkldnn::primitive>& pipeline) {  // NOLINT
     // create reorder primitive if the input format is not the preferred one
     auto local_key = key_ + suffix;
     auto key_reorder_p = key_ + suffix + "reorder_p";
@@ -218,7 +220,7 @@ class MKLDNNHandler {
     return target_memory_p;
   }
 
-  static std::string GetHash(mkldnn::memory::dims& operand_dims,
+  static std::string GetHash(mkldnn::memory::dims& operand_dims,  // NOLINT
                              const std::string& suffix) {
     auto dims2str = [](const mkldnn::memory::dims& operand_dims) {
       std::string dstr = "";
@@ -227,6 +229,7 @@ class MKLDNNHandler {
       }
       return dstr;
     };
+
     return dims2str(operand_dims) + suffix;
   }