Update tx_size assertions in rd search

The processing units support the rectangular transform block size.
Update the assertion conditions accordingly.

Change-Id: Iebd46dbbb04feaf161fb02f203fa2cde50b2b700
diff --git a/av1/encoder/encodemb.c b/av1/encoder/encodemb.c
index cd9587b..6b22d9e 100644
--- a/av1/encoder/encodemb.c
+++ b/av1/encoder/encodemb.c
@@ -1080,9 +1080,7 @@
     int bsl = tx_size_wide_unit[sub_txs];
     int i;
     assert(bsl > 0);
-#if CONFIG_EXT_TX
-    assert(tx_size < TX_SIZES);
-#endif  // CONFIG_EXT_TX
+    assert(tx_size < TX_SIZES_ALL);
 
     for (i = 0; i < 4; ++i) {
       const int offsetr = blk_row + ((i >> 1) * bsl);