Use table fetch for block width in block_rd_txfm

Make direct use of block_size_wide to fetch data for stride.

Change-Id: I0d8491e58cf00ea73c764d218cb56408b64d9ee7

av1/encoder/rdopt.c

@@ -1112,8 +1112,7 @@ static uint64_t sum_squares_2d(const int16_t *diff, int diff_stride,
 #endif  // CONFIG_EXT_TX
     default:
       assert(tx_size < TX_SIZES);
-      sse = aom_sum_squares_2d_i16(
-          diff, diff_stride, num_4x4_blocks_wide_txsize_lookup[tx_size] << 2);
+      sse = aom_sum_squares_2d_i16(diff, diff_stride, tx_size_wide[tx_size]);
       break;
   }
   return sse;
@@ -1157,7 +1156,7 @@ static void block_rd_txfm(int plane, int block, int blk_row, int blk_col,
 
       const int src_stride = p->src.stride;
       const int dst_stride = pd->dst.stride;
-      const int diff_stride = 4 * num_4x4_blocks_wide_lookup[plane_bsize];
+      const int diff_stride = block_size_wide[plane_bsize];
 
       const uint8_t *src = &p->src.buf[4 * (blk_row * src_stride + blk_col)];
       const uint8_t *dst = &pd->dst.buf[4 * (blk_row * dst_stride + blk_col)];