broadcast radio: add wrapper over HAL implementation

Add radio HAL wrapper in radio service to prepare migration to HIDL.

Bug: 31973526
Change-Id: I93fc6f00a2211f7ca425be73090f12b2855c9641
diff --git a/services/radio/Android.mk b/services/radio/Android.mk
index f5d74d3..c3178ea 100644
--- a/services/radio/Android.mk
+++ b/services/radio/Android.mk
@@ -18,7 +18,8 @@
 
 
 LOCAL_SRC_FILES:=               \
-    RadioService.cpp
+    RadioService.cpp \
+    RadioHalLegacy.cpp
 
 LOCAL_SHARED_LIBRARIES:= \
     libui \