Use TX_SIZE consistently instead of int.

Change-Id: If6e84f390c6f92e8e013056c657758ba9e407a71
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 7cc83b6..eb8f96a 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -368,9 +368,9 @@
 #endif
     const TX_SIZE tx_size = mbmi->tx_size;
     const int is_inter = is_inter_block(mbmi);
-    const int tx_size_ctx = get_tx_size_context(xd);
-    const int tx_size_cat = is_inter ? inter_tx_size_cat_lookup[bsize]
-                                     : intra_tx_size_cat_lookup[bsize];
+    const TX_SIZE tx_size_ctx = get_tx_size_context(xd);
+    const TX_SIZE tx_size_cat = is_inter ? inter_tx_size_cat_lookup[bsize]
+                                         : intra_tx_size_cat_lookup[bsize];
     const TX_SIZE coded_tx_size = txsize_sqr_up_map[tx_size];
     const int depth = tx_size_to_depth(coded_tx_size);
 #if CONFIG_EXT_TX && CONFIG_RECT_TX