Enable passthrough mode by default for audio, soundtrigger, and radio

Remove ENABLE_TREBLE flag usage for legacy hal fallback.
Introduce new build flag USE_LEGACY_LOCAL_AUDIO_HAL for fallback.

Bug: 32978887
Test: checked "OK Google" (from standby), Hangouts, YouTube,
      Play Music, fake radio hal + test app
KI: issues when using equializer and virtualuzer in Play Music

Change-Id: I1c279e622c885f799481f1287e0660ca576fcea0
diff --git a/services/radio/Android.mk b/services/radio/Android.mk
index 4344506..74f1fe0 100644
--- a/services/radio/Android.mk
+++ b/services/radio/Android.mk
@@ -30,9 +30,13 @@
     libradio \
     libradio_metadata
 
-ifeq ($(ENABLE_TREBLE),true)
+ifeq ($(USE_LEGACY_LOCAL_AUDIO_HAL),true)
+# libhardware configuration
+LOCAL_SRC_FILES +=               \
+    RadioHalLegacy.cpp
+else
 # Treble configuration
-LOCAL_CFLAGS += -DENABLE_TREBLE
+
 LOCAL_SRC_FILES += \
     HidlUtils.cpp \
     RadioHalHidl.cpp
@@ -43,13 +47,8 @@
     libhidltransport \
     libbase \
     android.hardware.broadcastradio@1.0
-else
-# libhardware configuration
-LOCAL_SRC_FILES +=               \
-    RadioHalLegacy.cpp
 endif
 
-
 LOCAL_CFLAGS += -Wall -Wextra -Werror
 
 LOCAL_MULTILIB := $(AUDIOSERVER_MULTILIB)