Fix a bug in vp10_predict_intra_block

Avoid mistakenly setting "have_right" as 0 for UV channel in blocks
of width no larger than 8.

Change-Id: Ic2b031e32f967a23fd118a052bf9edd7d5a3abe6

vp10/common/reconintra.c

@@ -1345,7 +1345,7 @@ void vp10_predict_intra_block(const MACROBLOCKD *xd, int bwl_in, int bhl_in,
   const BLOCK_SIZE bsize = xd->mi[0]->mbmi.sb_type;
   const struct macroblockd_plane *const pd = &xd->plane[plane];
   const int right_available =
-      mi_col + (bw >> !pd->subsampling_x) < xd->tile.mi_col_end;
+      mi_col + (1 << mi_width_log2_lookup[bsize]) < xd->tile.mi_col_end;
   const int have_right = vp10_has_right(bsize, mi_row, mi_col,
                                         right_available,
                                         tx_size, row_off, col_off,