Add code to handle voice radio technology of LTE.

Sometimes the Voice Radio Technology is reported as LTE but Voice
over LTE (VoLte) is not currently supported and for Sprint we
should default to CDMAPhone in that case. Otherwise the could stay
as a GSMPhone and handling voice calls will fail.

Bug: 10673760
Change-Id: Ic77411b5da415c620fce5a185ca1d7542dfe3b7f