Cellular: fix state machine to compile after master rebase

Fix automatic rebase error with cellulardevice.cpp

Author: Teppo Järvelin

features/cellular/framework/device/CellularDevice.cpp

@@ -117,10 +117,6 @@ nsapi_error_t CellularDevice::attach_to_network()
 
 nsapi_error_t CellularDevice::create_state_machine()
 {
-    _nw = open_network(_fh);
-    // Attach to network so we can get update status from the network
-    _nw->attach(callback(this, &CellularDevice::stm_callback));
-
     nsapi_error_t err = NSAPI_ERROR_OK;
     if (!_state_machine) {
         _nw = open_network(_fh);

features/cellular/framework/device/CellularStateMachine.cpp

@@ -406,7 +406,7 @@ void CellularStateMachine::state_sim_pin()
 
 void CellularStateMachine::state_signal_quality()
 {
-    _cb_data.error = _network->get_signal_quality(_signal_quality.rssi, &_signal_quality.ber);
+    _cb_data.error = _network.get_signal_quality(_signal_quality.rssi, &_signal_quality.ber);
 
     if (_cb_data.error != NSAPI_ERROR_OK) {
         retry_state_or_fail();