Fixed a bug in commit a4a5a210

Commit a4a5a210 enabled lossless coding, but the commit incorrectly
disabled the usage of skip in encoder even when skip should be used.
This commit make sure that skip is enabled even in lossless mode.

Change-Id: I276954f952c6ac68f17a316ebc72f09001228a08

vp9/encoder/vp9_rdopt.c

@@ -612,8 +612,9 @@ static void block_yrd_txfm(int plane, int block, BLOCK_SIZE plane_bsize,
 
   // TODO(jingning): temporarily enabled only for luma component
   rd = MIN(rd1, rd2);
-  if (!xd->lossless && plane == 0)
-    x->zcoeff_blk[tx_size][block] = rd1 > rd2 || !xd->plane[plane].eobs[block];
+  if (plane == 0)
+    x->zcoeff_blk[tx_size][block] = !xd->plane[plane].eobs[block] ||
+                                    (rd1 > rd2 && !xd->lossless);
 
   args->this_rate += args->rate;
   args->this_dist += args->dist;