message: Update mkl_concat_op.cc
  accross -> across
diff: @@ -484,7 +484,7 @@ class MklConcatOp : public OpKernel {
  output_tensor->flat<uint8>().size() * sizeof(uint8));
  }
  - // This method finds the most commom format accross all MKL inputs
  + // This method finds the most commom format across all MKL inputs
  // Inputs:
  // 1. input_shapes: shapes of input (MKL) tensors.
  // 2. concat_dim: concat dimension.
  