libnm: omit nm_device_*_get_hw_address() from introspection output
When the get_hw_address() method is called on a device object through GObject-introspection, the device-specific (e.g. nm_device_ethernet_get_hw_address()) C function is called instead of the more generic nm_device_get_hw_address().
Those device-specific functions were deprecated in commit 067a3d6c ('nm-device: expose via D-Bus the 'hw-address' property') and so libnm will print out deprecation warnings like:
DeprecationWarning: NM.DeviceEthernet.get_hw_address is deprecated
Omit the device-specific function from the introspection output so that the generic function will be called instead.