Telephony: Consider dataRegState to determine SPN display

There may be situations where voice service state is OOS and data
service state is IN_SERVICE. In such cases, both regStates need to be
considered to determine what to show in UI for SPN.

Change-Id: Iab17ed07611b6fd95d6bc6ee3e2e095f6700e3ba
CRs-Fixed: 532471