Inorder: Fix compilation of m5.fast.

printMemData is only used in DPRINTFs. If those are removed by compiling
m5.fast, that function is unused, gcc generates a warning, that gets turned
into an error, and the build fails. This change surrounds the function
definition with #if TRACING_ON so it only gets compiled in if the DPRINTFs do
to.

src/cpu/inorder/resources/cache_unit.cc

@@ -47,6 +47,7 @@ using namespace std;
 using namespace TheISA;
 using namespace ThePipeline;
 
+#if TRACING_ON
 static std::string
 printMemData(uint8_t *data, unsigned size)
 {
@@ -56,6 +57,7 @@ printMemData(uint8_t *data, unsigned size)
     }
     return dataStr.str();
 }
+#endif
 
 Tick
 CacheUnit::CachePort::recvAtomic(PacketPtr pkt)