Add @export to frontend scan enums

Test: make;
Change-Id: I9489ae28722e73de0aba7e83b115935546e8e357
diff --git a/tv/tuner/1.0/types.hal b/tv/tuner/1.0/types.hal
index 707f5df..d7628e2 100644
--- a/tv/tuner/1.0/types.hal
+++ b/tv/tuner/1.0/types.hal
@@ -1197,6 +1197,7 @@
 /**
  *  Scan type for Frontend.
  */
+@export
 enum FrontendScanType : uint32_t {
     SCAN_UNDEFINED = 0,
     SCAN_AUTO = 1 << 0,
@@ -1206,6 +1207,7 @@
 /**
  *  Scan Message Type for Frontend.
  */
+@export
 enum FrontendScanMessageType : uint32_t {
     /**
      * Scan locked the signal.