mem-ruby: MOESI_CMP_directory sync fix

The recent commit dd6cd33 modified the behaviour of the the Ruby
sequencer to handle load linked requests as loads rather than
stores. This caused the regression test
realview-simple-timing-dual-ruby-ARM-x86_64-opt
to become stuck when booting Linux. This patch fixes the issue by
adding a missing forward_eviction_to_cpu action to the state
transition(OM, Fwd_GETX, IM).

Change-Id: I8f253c5709488b07ddc5143a15eda406e31f3cc6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/28787
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/mem/ruby/protocol/MOESI_CMP_directory-L1cache.sm

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 ARM Limited
+ * Copyright (c) 2019-2020 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -1189,6 +1189,7 @@ machine(MachineType:L1Cache, "L1 cache protocol")
   // transition(OM, Fwd_GETX, OMF) {
   transition(OM, Fwd_GETX, IM) {
     ee_sendDataExclusive;
+    forward_eviction_to_cpu;
     l_popForwardQueue;
   }