Revert wrong uses of TX_SIZE enum.

Introduced by: https://aomedia-review.googlesource.com/c/aom/+/25181

Change-Id: I1f25178d6b273fbeade4c33f153b5f2bac4a8b99
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 515d48e..5076357 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -351,8 +351,8 @@
   if (block_signals_txsize(bsize)) {
     const TX_SIZE tx_size = mbmi->tx_size;
     const int is_inter = is_inter_block(mbmi);
-    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]
+    const int tx_size_ctx = get_tx_size_context(xd);
+    const int32_t 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);