Fix a baseline build error

Change-Id: I9b92caa9d65a3b062762c270c89018c8e08eba0f

av1/encoder/bitstream.c

@@ -3667,13 +3667,12 @@ static int get_refresh_mask_gf16(AV1_COMP *cpi) {
 #endif  // CONFIG_EXT_REFS
 
 static int get_refresh_mask(AV1_COMP *cpi) {
+  int refresh_mask = 0;
 #if CONFIG_EXT_REFS
 #if USE_GF16_MULTI_LAYER
   if (cpi->rc.baseline_gf_interval == 16) return get_refresh_mask_gf16(cpi);
 #endif  // USE_GF16_MULTI_LAYER
 
-  int refresh_mask = 0;
-
   // NOTE(zoeliu): When LAST_FRAME is to get refreshed, the decoder will be
   // notified to get LAST3_FRAME refreshed and then the virtual indexes for all
   // the 3 LAST reference frames will be updated accordingly, i.e.: