[LowerToHW][nfc] Use public, not friend private

Change two usages of private friend members to use public member
functions.  This is mildly cleaner and may enable future separation of two
structs.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

Author: seldridge

lib/Conversion/FIRRTLToHW/LowerToHW.cpp

@@ -690,13 +690,13 @@ void FIRRTLModuleLowering::runOnOperation() {
   });
   // Attach the lowered form of these annotations.
   if (!dutHierarchyFiles.empty())
-    state.oldToNewModuleMap[state.getDut()]->setAttr(
-        moduleHierarchyFileAttrName,
-        ArrayAttr::get(&getContext(), dutHierarchyFiles));
+    state.getNewModule(state.getDut())
+        ->setAttr(moduleHierarchyFileAttrName,
+                  ArrayAttr::get(&getContext(), dutHierarchyFiles));
   if (!testHarnessHierarchyFiles.empty())
-    state.oldToNewModuleMap[state.getTestHarness()]->setAttr(
-        moduleHierarchyFileAttrName,
-        ArrayAttr::get(&getContext(), testHarnessHierarchyFiles));
+    state.getNewModule(state.getTestHarness())
+        ->setAttr(moduleHierarchyFileAttrName,
+                  ArrayAttr::get(&getContext(), testHarnessHierarchyFiles));
 
   // Finally, lower all operations.
   auto result = mlir::failableParallelForEachN(