Fix getProgramList comment about possible result.

Also change default implementation results for not implemented calls
to be less harsh.

Test: instrumentation
Bug: b/36863239
Change-Id: I7f9adea8aa5b84aec81be13f5614ba16c8b74b75
diff --git a/broadcastradio/1.1/ITuner.hal b/broadcastradio/1.1/ITuner.hal
index dd7c844..7511629 100644
--- a/broadcastradio/1.1/ITuner.hal
+++ b/broadcastradio/1.1/ITuner.hal
@@ -65,6 +65,7 @@
      *               Client application MUST verify vendor/product name
      *               before setting this parameter to anything else.
      * @return result OK if the list was successfully retrieved.
+     *                INVALID_ARGUMENTS if invalid arguments are passed
      *                NOT_READY if the scan is in progress.
      *                NOT_STARTED if the scan has not been started, client may
      *                call startBackgroundScan to fix this.