Handle no bias vector in transpose_conv kernel (#1004)

Bias vector can be nullptr in tranpose_conv; hence
should do a check before deallocate.

BUG=#993
Co-authored-by: NTing Yan <94130036+tingyan19@users.noreply.github.com>

tensorflow/lite/micro/kernels/transpose_conv.cc

@@ -133,7 +133,9 @@ TfLiteStatus CalculateOpData(TfLiteContext* context, TfLiteNode* node,
     micro_context->DeallocateTempTfLiteTensor(input);
     micro_context->DeallocateTempTfLiteTensor(filter);
     micro_context->DeallocateTempTfLiteTensor(output);
-    micro_context->DeallocateTempTfLiteTensor(bias);
+    if (bias != nullptr) {
+      micro_context->DeallocateTempTfLiteTensor(bias);
+    }
   }
   return kTfLiteOk;
 }

tensorflow/lite/micro/kernels/xtensa/transpose_conv.cc

@@ -132,7 +132,9 @@ TfLiteStatus CalculateOpData(TfLiteContext* context, TfLiteNode* node,
     micro_context->DeallocateTempTfLiteTensor(input);
     micro_context->DeallocateTempTfLiteTensor(output);
     micro_context->DeallocateTempTfLiteTensor(filter);
-    micro_context->DeallocateTempTfLiteTensor(bias);
+    if (bias != nullptr) {
+      micro_context->DeallocateTempTfLiteTensor(bias);
+    }
   }
   return kTfLiteOk;
 }