mem: avoid calling regStat twice on a QoSPolicy

Change-Id: I216c57073fabe29c3f898a5d89cee41efd4277d5
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13696
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/qos/mem_ctrl.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 ARM Limited
+ * Copyright (c) 2017-2018 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -329,9 +329,6 @@ MemCtrl::regStats()
         priorityMinLatency.subname(j, std::to_string(j));
         priorityMaxLatency.subname(j, std::to_string(j));
     }
-
-    if (policy)
-        policy->regStats();
 }
 
 void