Cdma: Fix 3G reported as unknown on certain devices

Some older CDMA RILs only report VoiceRadioTechnology which
results in network Unknown. In these cases return
RilVoiceRadioTechnology for RilDataRadioTechnology.
Set ro.telephony.ril.v3=usevoicetechfordata to enable

Adapted from LTE by: http://review.cyanogenmod.org/#/c/50230/