[tilelink2] allow TL monitors to be globally enabled or disabled (#392)

src/main/scala/rocketchip/Configs.scala

@@ -33,6 +33,7 @@ class BasePlatformConfig extends Config(
           dataBits = edgeDataBits,
           addrBits = site(PAddrBits),
           idBits = site(EdgeIDBits))
+        case TLEmitMonitors => true
         case TLKey("EdgetoSlave") =>
           site(TLKey("L1toL2")).copy(dataBeats = edgeDataBeats)
         case TLKey("MCtoEdge") =>
@@ -201,3 +202,17 @@ class With64BitPeriphery extends Config (
     case PeripheryBusKey => PeripheryBusConfig(arithAMO = true, beatBytes = 8)
   }
 )
+
+class WithTLMonitors extends Config (
+  (pname, site, here) => pname match {
+    case TLEmitMonitors => true
+    case _ => throw new CDEMatchError
+  }
+)
+
+class WithoutTLMonitors extends Config (
+  (pname, site, here) => pname match {
+    case TLEmitMonitors => false
+    case _ => throw new CDEMatchError
+  }
+)