trace: reimplement the DTRACE function so it doesn't use a vector

At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing.  This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help

src/cpu/o3/commit_impl.hh

@@ -54,6 +54,10 @@
 #include "cpu/o3/thread_state.hh"
 #include "cpu/exetrace.hh"
 #include "cpu/timebuf.hh"
+#include "debug/Activity.hh"
+#include "debug/Commit.hh"
+#include "debug/CommitRate.hh"
+#include "debug/ExecFaulting.hh"
 #include "params/DerivO3CPU.hh"
 #include "sim/faults.hh"