hal: add missing flags for extended features

- add missing feature flags and definitions
  to compile hal without extended features
  enabled.

Change-Id: I8c04ae54e6597ed43de60b2d01ca333070aef675
diff --git a/hal/Android.mk b/hal/Android.mk
index 87ebeea..bc17a57 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -37,6 +37,10 @@
 
 LOCAL_SRC_FILES += audio_extn/audio_extn.c
 
+ifneq ($(strip $(AUDIO_FEATURE_DISABLED_PCM_OFFLOAD)),true)
+    LOCAL_CFLAGS += -DPCM_OFFLOAD_ENABLED
+endif
+
 ifneq ($(strip $(AUDIO_FEATURE_DISABLED_ANC_HEADSET)),true)
     LOCAL_CFLAGS += -DANC_HEADSET_ENABLED
 endif