Fix txb_w/h use case in av1_tx_block_rd_b()

Match them with block_row/col index.

Change-Id: Idf0f924a093e5312b0a36b765d295e52d033eb5a
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index 4922d61..3dfa2ee 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -3013,8 +3013,8 @@
     inv_txfm_add(dqcoeff, rec_buffer, MAX_TX_SIZE, &inv_txfm_param);
 #endif  // CONFIG_AOM_HIGHBITDEPTH
 
-    if (txb_h + blk_col > max_blocks_wide ||
-        txb_w + blk_row > max_blocks_high) {
+    if (txb_w + blk_col > max_blocks_wide ||
+        txb_h + blk_row > max_blocks_high) {
       int idx, idy;
       unsigned int this_dist;
       int blocks_height = AOMMIN(txb_h, max_blocks_high - blk_row);