libaudiohal@aidl: Implement gain change via 'setPortConfig'

The path of updating gain of a port config was not implemented
properly resulting in the update not being sent to the HAL.

Bug: 345852128
Test: atest CoreAudioHalAidlTest
Change-Id: I4ed81a57178fd6f37085c86a0dc98c0c32302f46
diff --git a/media/libaudiohal/impl/Hal2AidlMapper.h b/media/libaudiohal/impl/Hal2AidlMapper.h
index c70c8af..710b43e 100644
--- a/media/libaudiohal/impl/Hal2AidlMapper.h
+++ b/media/libaudiohal/impl/Hal2AidlMapper.h
@@ -163,6 +163,7 @@
     status_t findOrCreateDevicePortConfig(
             const ::aidl::android::media::audio::common::AudioDevice& device,
             const ::aidl::android::media::audio::common::AudioConfig* config,
+            const ::aidl::android::media::audio::common::AudioGainConfig* gainConfig,
             ::aidl::android::media::audio::common::AudioPortConfig* portConfig,
             bool* created);
     // If the resulting 'portConfig->id' is 0, that means the config was not created,