fix unpack bit bug

mindspore/lite/tools/converter/legacy_optimizer/graph/set_unused_quant_param_to_default_pass.cc

@@ -24,7 +24,6 @@ STATUS SetUnusedQuantParamToDefaultPass::Run(schema::MetaGraphT *graph) {
       quant_param->min = 0;
       quant_param->max = 0;
       quant_param->narrowRange = true;
-      quant_param->numBits = 8;
       quant_param->dstDtype = TypeId::kNumberTypeFloat32;
     }
   }