Clear out ambiguity in broadcastradio@2.0 comments.

Bug: 76798863
Test: it builds
Change-Id: Icd13a187d3a002e6d1d0af8d360de31a75949b69
diff --git a/broadcastradio/2.0/ITunerCallback.hal b/broadcastradio/2.0/ITunerCallback.hal
index ede8350..b20a0b2 100644
--- a/broadcastradio/2.0/ITunerCallback.hal
+++ b/broadcastradio/2.0/ITunerCallback.hal
@@ -17,12 +17,14 @@
 
 interface ITunerCallback {
     /**
-     * Method called by the HAL when a tuning operation fails
+     * Method called by the HAL when a tuning operation fails asynchronously
      * following a step(), scan() or tune() command.
      *
-     * @param result OK if tune succeeded;
-     *               TIMEOUT in case of time out.
-     * @param selector A ProgramSelector structure passed from tune(),
+     * This callback is only called when the step(), scan() or tune() command
+     * returned OK at first.
+     *
+     * @param result TIMEOUT in case of time out.
+     * @param selector A ProgramSelector structure passed from tune() call;
      *                 empty for step() and scan().
      */
     oneway onTuneFailed(Result result, ProgramSelector selector);