audio_policy: modify few methods to appropriately override base

Few methods in AudioPolicyManagerCustom is not overriding its
base implemenation due to signature mismatch. Since they act
as separate method they are not getting called to override
base implemenation.
Correct signatures to implement overriding instead of overloading.
Remove custom stopOutput implementation since it is not adding
any change w.r.t. base implementation.

Change-Id: I6fe8fd6890ee8e896b6430f3ad170850d77b17d5
diff --git a/policy_hal/AudioPolicyManager.h b/policy_hal/AudioPolicyManager.h
index 69b2b1f..1572d0e 100644
--- a/policy_hal/AudioPolicyManager.h
+++ b/policy_hal/AudioPolicyManager.h
@@ -81,7 +81,7 @@
 
          status_t checkAndSetVolume(audio_stream_type_t stream,
                                                    int index,
-                                                   const sp<SwAudioOutputDescriptor>& outputDesc,
+                                                   const sp<AudioOutputDescriptor>& outputDesc,
                                                    audio_devices_t device,
                                                    int delayMs = 0, bool force = false);
 
@@ -93,17 +93,14 @@
                                            bool fromCache);
         // returns true if given output is direct output
         bool isDirectOutput(audio_io_handle_t output);
-        status_t stopOutput(audio_io_handle_t output,
-                                    audio_stream_type_t stream,
-                                    audio_session_t session);
 
         // if argument "device" is different from AUDIO_DEVICE_NONE,  startSource() will force
         // the re-evaluation of the output device.
-        status_t startSource(sp<SwAudioOutputDescriptor> outputDesc,
+        status_t startSource(sp<AudioOutputDescriptor> outputDesc,
                              audio_stream_type_t stream,
                              audio_devices_t device,
                              uint32_t *delayMs);
-         status_t stopSource(sp<SwAudioOutputDescriptor> outputDesc,
+         status_t stopSource(sp<AudioOutputDescriptor> outputDesc,
                             audio_stream_type_t stream,
                             bool forceDeviceUpdate);
         // event is one of STARTING_OUTPUT, STARTING_BEACON, STOPPING_OUTPUT, STOPPING_BEACON