mem-cache: Only pendingModified MSHRs can satisfy CMO snoops

We set the satisfied flag when a cache clean request encounters:
1) a block with the dirty bit set, or
2) a pending modified MSHR which means that the cache will get copy of
the block that will be soon modified.

This changeset fixes a previous bug that set the satisfied flag on
snooping MSHR hits even the pendingModified flags was not set.

Change-Id: I4968c4820997be5cc1238148eea12a1ba39837d4
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Sudhanshu Jha <sudhanshu.jha@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/7822
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

src/mem/cache/mshr.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012-2013, 2015-2017 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2018 ARM Limited
  * All rights reserved.
  *
  * The license below extends only to copyright in the software and shall
@@ -452,7 +452,7 @@ MSHR::handleSnoop(PacketPtr pkt, Counter _order)
             postInvalidate = true;
         }
 
-        if (pkt->isClean()) {
+        if (isPendingModified() && pkt->isClean()) {
             pkt->setSatisfied();
         }
     }