cpu-o3: test 2 fetch

Change-Id: Iaa4a853508ae80e412a8b3bdd41dea26d9eb8c29

Author: jensen-yan

configs/example/kmhv3.py

@@ -108,6 +108,8 @@ def setKmhV3Params(args, system):
             cpu.branchPred.mgsc.enabled = False
             cpu.branchPred.ras.enabled = True
 
+            cpu.branchPred.enable2Fetch = True
+
         # l1 cache per core
         if args.caches:
             cpu.icache.size = '64kB'