tilelink2: add an executable manager parameter

src/main/scala/uncore/tilelink2/SRAM.scala

@@ -9,6 +9,7 @@ class TLRAM(address: AddressSet, beatBytes: Int = 4) extends LazyModule
   val node = TLManagerNode(beatBytes, TLManagerParameters(
     address            = List(address),
     regionType         = RegionType.UNCACHED,
+    executable         = true,
     supportsGet        = TransferSizes(1, beatBytes),
     supportsPutPartial = TransferSizes(1, beatBytes),
     supportsPutFull    = TransferSizes(1, beatBytes),