stdlib: Fix the chi protocol of arm boot tests (#658)

Change-Id: I63f17a73b2e16bc26d9b41babc63439a6040791f

src/python/gem5/components/cachehierarchies/chi/nodes/directory.py

@@ -61,6 +61,7 @@ class SimpleDirectory(AbstractNode):
         self.sequencer = NULL
 
         self.use_prefetcher = False
+        self.prefetcher = NULL
 
         # Set up home node that allows three hop protocols
         self.is_HN = True

src/python/gem5/components/cachehierarchies/chi/nodes/dma_requestor.py

@@ -25,6 +25,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 from m5.objects import (
+    NULL,
     ClockDomain,
     RubyCache,
 )
@@ -67,6 +68,7 @@ class DMARequestor(AbstractNode):
 
         self.send_evictions = False
         self.use_prefetcher = False
+        self.prefetcher = NULL
         # Some reasonable default TBE params
         self.number_of_TBEs = 16
         self.number_of_repl_TBEs = 1

src/python/gem5/components/cachehierarchies/chi/nodes/private_l1_moesi_cache.py

@@ -25,6 +25,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 from m5.objects import (
+    NULL,
     ClockDomain,
     RubyCache,
     RubyNetwork,
@@ -56,6 +57,7 @@ class PrivateL1MOESICache(AbstractNode):
         self.clk_domain = clk_domain
         self.send_evictions = core.requires_send_evicts()
         self.use_prefetcher = False
+        self.prefetcher = NULL
 
         # Only applies to home nodes
         self.is_HN = False