Updates to make traces work correctly in all circumstances. Add opt set associative simulation.

cpu/trace/opt_cpu.cc:
cpu/trace/opt_cpu.hh:
    Add the ability to simulate less than fully-associative opt caches.
cpu/trace/reader/itx_reader.cc:
    Add writeback to the command list.

--HG--
extra : convert_revision : a9c9c4be3358f4083d7e85772620441a3ad809db

cpu/trace/reader/itx_reader.cc

@@ -161,6 +161,9 @@ ITXReader::getNextReq(MemReqPtr &req)
                   case ITXWrite:
                     tmp_req->cmd = Write;
                     break;
+                  case ITXWriteback:
+                    tmp_req->cmd = Writeback;
+                    break;
                   case ITXCode:
                     tmp_req->cmd = Read;
                     tmp_req->flags |= INST_READ;