Don't write blank baseband version

* There's no point in setting the baseband version if the returned value
  is blank anyway.

Change-Id: Ica9973a8b790c0de6afa10bc131257a3a03f18a0
CdmaLte: Fix 3G reported as unknown on certain devices

Some older CDMA/LTE RILs only report VoiceRadioTechnology which
results in network Unknown. In these cases return
RilVoiceRadioTechnology for RilDataRadioTechnology.

Set ro.telephony.ril.config=usevoicetechfordata to enable

Change-Id: Icfbc8739993beae1b0f024bf71374751aa200a01