Make TTY broadcasts protected

Currently, any app can broadcast the intent to update the TTY mode. This
change updates the intents to protected broadcasts so that only system
can broadcast them. Otherwise, a SecurityException will be thown.

Bug: 29832693
Change-Id: Ic9a91be3d8d15043e3165b766348cff301dd5da1
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index b8225c9..545aa8b 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -24,6 +24,8 @@
 
     <original-package android:name="com.android.phone" />
 
+    <protected-broadcast android:name="android.telecom.action.TTY_PREFERRED_MODE_CHANGED" />
+    <protected-broadcast android:name="android.telecom.action.CURRENT_TTY_MODE_CHANGED" />
     <protected-broadcast android:name="android.intent.action.SERVICE_STATE" />
     <protected-broadcast android:name="android.intent.action.RADIO_TECHNOLOGY" />
     <protected-broadcast android:name="android.intent.action.EMERGENCY_CALLBACK_MODE_CHANGED" />