Add exported-to-kati namespaces to root namespace

This lets us use boot jar modules that are hidden behind
soong_namespace.

Change-Id: If0068387efdeca5458b5b97ce6b993b10a268bd2
diff --git a/android/namespace.go b/android/namespace.go
index ebf85a1..3b9ae3a 100644
--- a/android/namespace.go
+++ b/android/namespace.go
@@ -156,6 +156,9 @@
 			return fmt.Errorf("a namespace must be the first module in the file")
 		}
 	}
+	if (namespace.exportToKati) {
+		r.rootNamespace.visibleNamespaces = append(r.rootNamespace.visibleNamespaces, namespace)
+	}
 	r.sortedNamespaces.add(namespace)
 
 	r.namespacesByDir.Store(namespace.Path, namespace)