GsmSS: Use per-slot resources for carrier-bound options

The decision of whether an MVNO operator is roaming or not comes from
an mcc/mnc-specific resource. Relying on the global system resources
to provide the appropriate result for each of the slots on a multi-SIM
device is just wrong, since each SIM will have (and need) its own
separate preferences and arrays of compatible/blocked carriers.

Ref CYNGNOS-2534, CYNGNOS-3190

Change-Id: If3b45a4a4702cf45bc1d965e26c8df7ef3ff783b