message: Simplify MakeBlockMap: it already assumes that the input rows/columns
  are rounded up to next multiple of kernel block dims.
diff: @@ -91,6 +91,8 @@ void MakeBlockMap(int rows, int cols, int depth, int kernel_rows,
  gemmlowp::ScopedProfilingLabel label("MakeBlockMap");
  RUY_DCHECK_GE(rows, kernel_rows);
  RUY_DCHECK_GE(cols, kernel_cols);
  + RUY_DCHECK_EQ(rows % kernel_rows, 0);
  + RUY_DCHECK_EQ(cols % kernel_cols, 0);
  block_map->traversal_order = BlockMapTraversalOrder::kLinear;
  if (RUY_OPT_ENABLED(RUY_OPT_FRACTAL) &&
  @@ -171,25 +173,20 @@ void MakeBlockMap(int rows, int cols, int depth, int kernel_rows,
  int num_blocks_base_log2 = size_floor_log2 - l1_size_log2;
  RUY_DCHECK_GE(num_blocks_base_log2, 0);
  - int rows_rounded_up = round_up_pot(rows, kernel_rows);
  - int cols_rounded_up = round_up_pot(cols, kernel_cols);
  -
  const int num_blocks_of_rows_log2 =
  num_blocks_base_log2 + rows_rectangularness_log2;
  const int num_blocks_of_cols_log2 =
  num_blocks_base_log2 + cols_rectangularness_log2;
  const int smallr =
  - round_down_pot(rows_rounded_up >> num_blocks_of_rows_log2, kernel_rows);
  + round_down_pot(rows >> num_blocks_of_rows_log2, kernel_rows);
  const int smallc =
  - round_down_pot(cols_rounded_up >> num_blocks_of_cols_log2, kernel_cols);
  + round_down_pot(cols >> num_blocks_of_cols_log2, kernel_cols);
  const int missr =
  - round_up_pot(rows_rounded_up - (smallr << num_blocks_of_rows_log2),
  - kernel_rows) /
  + round_up_pot(rows - (smallr << num_blocks_of_rows_log2), kernel_rows) /
  kernel_rows;
  const int missc =
  - round_up_pot(cols_rounded_up - (smallc << num_blocks_of_cols_log2),
  - kernel_cols) /
  + round_up_pot(cols - (smallc << num_blocks_of_cols_log2), kernel_cols) /
  kernel_cols;
  block_map->dims[Side::kLhs] = rows;
  