Do not try to perform feature/capability specific actions if we're still
unlocked, as the modem didn't yet export the feature/capability specific
interface.
The only interfaces expected while modem is unlocked are the Modem and Simple
interfaces, as well as the SIM interface in the SIM object, of course.
We provide `--3gpp-register-home' to request automatic registration. This will
try to register in the home network if available; and if not available, in any
other network being allowed.
We also provide `--3gpp-register-in-operator' to try to lock the registration
in the network of a given specific operator, specified by MCCMNC.
