[rilmodem] Add support for new RIL API radio tech definition

Map new RADIO_TECH_DC_HSDPA RIL API definition correctly

Signed-off-by: Petri Takalokastari <petri.takalokastari@oss.tieto.com>
Merge pull request #74 from ptakalok/master

[rilmodem] Add support for new RIL API radio tech definition