Revert "Hide CarrierPrivilege APIs in TelMgr."

This reverts commit b7aa9e4a6338811d4dacc77e6024a0b97a99e5e9.

Change-Id: I212cd4f1b7b45e0523fc47b2a9c2a6b487e9dbb5
diff --git a/telecomm/java/android/telecom/PhoneAccount.java b/telecomm/java/android/telecom/PhoneAccount.java
index 9ab7ffa..4b059b2 100644
--- a/telecomm/java/android/telecom/PhoneAccount.java
+++ b/telecomm/java/android/telecom/PhoneAccount.java
@@ -283,6 +283,9 @@
      * The raw callback number used for this {@code PhoneAccount}, as distinct from
      * {@link #getAddress()}. For the majority of {@code PhoneAccount}s this should be registered
      * as {@code null}.  It is used by the system for SIM-based {@code PhoneAccount} registration
+     * where {@link android.telephony.TelephonyManager#setLine1NumberForDisplay(String, String)}
+     * has been used to alter the callback number.
+     * <p>
      *
      * @return The subscription number, suitable for display to the user.
      */