Add features for Automotive usecases.

1. Add support for emergency announcements - If the CAR wants to make an
emergency announcements.

Change-Id: Id4394e9ebce09d08ea4a4922032393bf2c2cddf4
(cherry picked from commit b0e3867fc5bdb09d18aeb0f111998852aeaf7f86)
diff --git a/services/radio/RadioService.cpp b/services/radio/RadioService.cpp
index cd0f5f3..57697f3 100644
--- a/services/radio/RadioService.cpp
+++ b/services/radio/RadioService.cpp
@@ -349,6 +349,7 @@
         }
         break;
     case RADIO_EVENT_TA:
+    case RADIO_EVENT_EA:
     case RADIO_EVENT_ANTENNA:
     case RADIO_EVENT_CONTROL:
         event->on = halEvent->on;