TLBuffer: move TLBufferParams to diplomacy.BufferParams

src/main/scala/diplomacy/Parameters.scala

@@ -219,3 +219,20 @@ object AddressSet
     if (out.size != n) unify(out) else out.toList
   }
 }
+
+case class BufferParams(depth: Int, flow: Boolean, pipe: Boolean)
+{
+  require (depth >= 0)
+  def isDefined = depth > 0
+  def latency = if (isDefined && !flow) 1 else 0
+}
+
+object BufferParams
+{
+  implicit def apply(depth: Int): BufferParams = BufferParams(depth, false, false)
+
+  val default = BufferParams(2)
+  val none    = BufferParams(0)
+  val flow    = BufferParams(1, true, false)
+  val pipe    = BufferParams(1, false, true)
+}