audio: Add support to enable split A2DP

- Add new audio extension module for a2dp
- Add support to configure AFE encoder based
  on BT device capabilities
- Add support for soft handoff to re-configure
  AFE based on new BT device capability

Change-Id: I5d710fda1a8d8fa3b5d85aaa2b3096cff8fd7ce5
diff --git a/hal/Android.mk b/hal/Android.mk
index 83787e3..adee78b 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -243,6 +243,11 @@
     LOCAL_SRC_FILES += audio_extn/source_track.c
 endif
 
+ifeq ($(strip $(AUDIO_FEATURE_ENABLED_SPLIT_A2DP)),true)
+    LOCAL_CFLAGS += -DSPLIT_A2DP_ENABLED
+    LOCAL_SRC_FILES += audio_extn/a2dp.c
+endif
+
 LOCAL_SHARED_LIBRARIES := \
 	liblog \
 	libcutils \
@@ -251,6 +256,7 @@
 	libaudioroute \
 	libdl \
 	libaudioutils \
+	libhardware \
 	libexpat
 
 LOCAL_C_INCLUDES += \