rocketchip: all of the address map now comes from TL2

src/main/scala/junctions/addrmap.scala

@@ -76,12 +76,7 @@ class AddrMap(
     var cacheable = true
     for (AddrMapEntry(name, r) <- entriesIn) {
       require (!mapping.contains(name))
-
-      if (r.start != 0) {
-        base = r.start
-      } else {
-        base = (base + r.size - 1) / r.size * r.size
-      }
+      base = r.start
 
       r match {
         case r: AddrMap =>