notifyCarrierNetworkChange:TelephonyManager->CarrierService

Per API review, move TelephonyManager.notifyCarrierNetworkChange() to
CarrierService.notifyCarrierNetworkChange(). Underlying telephony
implementation remains unchanged.

Also minor tweaks to CarrierService:
* Remove some unnecessary @hide
* Remove final qualifier from onBind() so that subclasses can handle
  new internal callers that want to bind to it.

Bug: 21572049
Bug: 21630803
Change-Id: Idcbcd107966fe92d7edc23c261e11db61160f615