Add background scan routines and callbacks to broadcast radio HAL.

Bug: b/34054813
Test: existing VTS pass, none added.
Change-Id: I2009e73a9e5edc4752366fd84f67b5a745856441
diff --git a/broadcastradio/1.1/default/Tuner.cpp b/broadcastradio/1.1/default/Tuner.cpp
index b4eb184..f280754 100644
--- a/broadcastradio/1.1/default/Tuner.cpp
+++ b/broadcastradio/1.1/default/Tuner.cpp
@@ -200,6 +200,10 @@
     return Void();
 }
 
+Return<ProgramListResult> Tuner::startBackgroundScan() {
+    return ProgramListResult::NOT_INITIALIZED;
+}
+
 Return<void> Tuner::getProgramList(const hidl_string& filter __unused, getProgramList_cb _hidl_cb) {
     hidl_vec<ProgramInfo> pList;
     // TODO(b/34054813): do the actual implementation.