MMLocation3gpp provides MCC/MNC information as integers, so it can not
make distinction between operator codes such as XXX01 and XXX001.
This commit deprecates mm_location_3gpp_get_mobile_network_code() and
implements a new function mm_location_3gpp_get_operator_code() which
provides the MCC+MNC in string format.
The mm_location_3gpp_get_mobile_country_code() is still available as
returning the MCC as an integer does not have ambiguity issues.
879ec1a5d4