[SystemInfo] add system_info_network_ivi.cc to fit tizen ivi/common.

Follow system_info_sim_ivi.cc(#369), add system_info_network_ivi.cc to fit ivi system.

BUG=XWALK-2361
By 'enumerate' I meant using GetModems. Sorry for lack of clarity. Now it looks better. Although if there are multiple modems, you should check the modem type as well, and have an algorithm to check the existence of "hardware" or "sap" or "hfp" modems, in this order, and choose the first match. You may also exclude "hfp" modems from system info.