Fix TCQ assertion failure in windows VS

There is an assertion failure and encoder crash for research-v9.0.0-rc1 in windows with VS 2022. This MR is fixing this problem.

Fix issue #574

(cherry picked from commit 1281cc981cdb8472bd0880a74cc66c09360822a4)
diff --git a/av1/encoder/trellis_quant.h b/av1/encoder/trellis_quant.h
index e2c6be3..11b800c 100644
--- a/av1/encoder/trellis_quant.h
+++ b/av1/encoder/trellis_quant.h
@@ -33,7 +33,7 @@
   int64_t rdCost : 64;
   int32_t rate : 32;
   int32_t absLevel : 24;
-  int8_t prevId : 8;
+  int32_t prevId : 8;
 } tcq_node_t;
 
 typedef struct tcq_ctx_t {