trusty: Export ConfirmationUI helper classes

And fix namespaces.

Bug: 174402999
Test: m
Change-Id: I54dcc92d8c153d0fa2b10b2679a9a871699de8b1
diff --git a/trusty/confirmationui/TrustyConfirmationUI.h b/trusty/confirmationui/TrustyConfirmationUI.h
index 3a7c7ef..0bd703c 100644
--- a/trusty/confirmationui/TrustyConfirmationUI.h
+++ b/trusty/confirmationui/TrustyConfirmationUI.h
@@ -43,7 +43,7 @@
 using ::android::hardware::Return;
 using ::android::hardware::Void;
 
-using ::android::trusty::TrustyApp;
+using ::android::trusty::confirmationui::TrustyApp;
 
 class TrustyConfirmationUI : public IConfirmationUI {
   public: