hal: add support to use low lantecy as primay output

- Add support to use low lantency output as primary
  output when AUDIO_USE_LL_AS_PRIMARY_OUTPUT is enabled

Change-Id: Ie7faf9f7af4c97b7afdda8084b7acf162abbc0b6
diff --git a/hal/Android.mk b/hal/Android.mk
index 05d3e82..c67f390 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -56,6 +56,10 @@
     LOCAL_SRC_FILES += edid.c
 endif
 
+ifeq ($(strip $(AUDIO_USE_LL_AS_PRIMARY_OUTPUT)),true)
+    LOCAL_CFLAGS += -DUSE_LL_AS_PRIMARY_OUTPUT
+endif
+
 ifeq ($(strip $(AUDIO_FEATURE_ENABLED_PCM_OFFLOAD)),true)
     LOCAL_CFLAGS += -DPCM_OFFLOAD_ENABLED
 endif