Rename USAGE_NOTIFICATION_TELEPHONY_RINGTONE

AudioAttributes: rename USAGE_NOTIFICATION_TELEPHONY_RINGTONE to
  USAGE_NOTIFICATION_RINGTONE in the list of usage values.
Temporarily keep the old definition to prevent transient build
  breakages, will be removed after telephony packages have been
  updated.

Bug 16401631

Change-Id: I9398443fd7ba3c30e9d371c5c5a2934b9ea6f30a