Prepare openInput() signature to AIDL conversion

The purpose is to avoid having more than one primitive output argument
and to avoid in/out arguments.

Test: Audio-related CTS tests from CtsMediaTestCases
Change-Id: I6bb5dde7956dcca30ed874397f78658d79433202
diff --git a/media/libaudioclient/Android.bp b/media/libaudioclient/Android.bp
index 423d98f..dacec15 100644
--- a/media/libaudioclient/Android.bp
+++ b/media/libaudioclient/Android.bp
@@ -298,6 +298,8 @@
         "aidl/android/media/CreateRecordResponse.aidl",
         "aidl/android/media/CreateTrackRequest.aidl",
         "aidl/android/media/CreateTrackResponse.aidl",
+        "aidl/android/media/OpenInputRequest.aidl",
+        "aidl/android/media/OpenInputResponse.aidl",
 
         "aidl/android/media/IAudioFlingerClient.aidl",
         "aidl/android/media/IAudioRecord.aidl",