hal: Add support for AUXPCM BT

Atheros BT chip uses AUXPCM instead of slimbus. Audio HAL has
to use different mixer paths file depending on whether it's
internal or external BT chip

Change-Id: I78ae70462fed42d4260ae37070ba23e81779c866
diff --git a/hal/Android.mk b/hal/Android.mk
index 44e6862..f20105c 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -90,6 +90,10 @@
     LOCAL_SRC_FILES += audio_extn/listen.c
 endif
 
+ifeq ($(strip $(AUDIO_FEATURE_ENABLED_AUXPCM_BT)),true)
+    LOCAL_CFLAGS += -DAUXPCM_BT_ENABLED
+endif
+
 LOCAL_MODULE := audio.primary.$(TARGET_BOARD_PLATFORM)
 
 LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw