Refactor to use block_size_wide/high[] consistently

Replace the computation of block size in pixels with lookup table
directly.

Change-Id: I39589b2bc1d20372969ff5ad0f60639e64a19b41
diff --git a/av1/encoder/rd.c b/av1/encoder/rd.c
index e1bfdf4..190e07e 100644
--- a/av1/encoder/rd.c
+++ b/av1/encoder/rd.c
@@ -717,7 +717,7 @@
 
 int16_t *av1_raster_block_offset_int16(BLOCK_SIZE plane_bsize, int raster_block,
                                        int16_t *base) {
-  const int stride = 4 * num_4x4_blocks_wide_lookup[plane_bsize];
+  const int stride = block_size_wide[plane_bsize];
   return base + av1_raster_block_offset(plane_bsize, raster_block, stride);
 }