Check enough work is queued before queueing more in avalon_fill.

driver-avalon.c

@@ -768,6 +768,8 @@ static bool avalon_fill(struct cgpu_info *avalon)
 
 	if (unlikely(!work))
 		return false;
+	if (avalon->queued == avalon_info[avalon->device_id]->miner_count)
+		return true;
 	avalon->works[avalon->queued++] = work;
 	if (avalon->queued == avalon_info[avalon->device_id]->miner_count)
 		return true;