WIP Toggle power roles
This automatically enables power when serving as source and disables it when acting as sink doing away with the manual step in https://source.puri.sm/Librem5/linux-next/-/merge_requests/215#note_118447.
Obviously not ready to be merge. @angus.ainslie i only added minimal stubs to not interfere with your PD work (so it does not care about negotiating sink currents etc) it uses the .external_power_changed
hooks the Heikki mentioned in https://lore.kernel.org/lkml/20200921143757.GG1630537@kuha.fi.intel.com/ thogh so maybe that is of use to you too (building on the initial power-supply support i added way back to the tps6598x driver).
Obviously by no means read to be merged due to tons of debugging and only minimal testing.