The atm/adsl plugin really is a generic ATM plugin but (a) it needs a
bit of work to do IPoATM rather than just PPPoATM and PPPoEoATM, and
(b) most people currently using NM's ATM support are using DSL devices
not actual ATM cards anyway, and have no idea what "ATM" even means.
If we add the necessary IPoATM support later we can rename the plugin
back to -atm