hal: add DSDA support on APQ targets

-This change adds DSDA support for APQ based targets
 where external modem is used for voice calls.
-Add new CSD API to support local call hold.

Change-Id: I7743a1df43dc1abac4e325ff104ec1bb64c9e12b
diff --git a/hal/platform_api.h b/hal/platform_api.h
index 66b090e..6c64073 100644
--- a/hal/platform_api.h
+++ b/hal/platform_api.h
@@ -19,6 +19,7 @@
 
 #ifndef AUDIO_PLATFORM_API_H
 #define AUDIO_PLATFORM_API_H
+#include <sound/voice_params.h>
 
 void *platform_init(struct audio_device *adev);
 void platform_deinit(void *platform);
@@ -63,6 +64,8 @@
 int platform_stop_incall_recording_usecase(void *platform);
 int platform_start_incall_music_usecase(void *platform);
 int platform_stop_incall_music_usecase(void *platform);
+int platform_update_lch(void *platform, struct voice_session *session,
+                        enum voice_lch_mode lch_mode);
 /* returns the latency for a usecase in Us */
 int64_t platform_render_latency(audio_usecase_t usecase);
 int platform_update_usecase_from_source(int source, audio_usecase_t usecase);