only write out finish from tile 0 in groundtest

groundtest/src/main/scala/tile.scala

@@ -151,6 +151,8 @@ class GroundTestTile(id: Int, resetSignal: Bool)
   ptw.io.requestors(0) <> test.io.ptw
   ptw.io.requestors(1) <> dcache.io.ptw
 
+  // Only Tile 0 needs to write tohost
+  if (id == 0) {
     val finisher = Module(new GroundTestFinisher)
     finisher.io.finished := test.io.finished
 
@@ -158,4 +160,5 @@ class GroundTestTile(id: Int, resetSignal: Bool)
     memArb.io.in(0) <> test.io.mem
     memArb.io.in(1) <> finisher.io.mem
     io.uncached.head <> memArb.io.out
+  } else { io.uncached.head <> test.io.mem }
 }