drivers: modem: sim7080: added stop functions for network and gnss

Network and gnss can be disabled with stop functions instead of power
cycling the modem. The start functions will also not power cycle the
modem. In order to call the start functions the modem needs to be
booted.

Signed-off-by: Lukas Gehreke <lk.gehreke@gmail.com>
4 files changed