There are now multiple plugins using drm_dp_aux_dev interface which
may potentially be combined with an amdgpu. Prevent exercising this
interface with any plugin using DP aux unless a new enough kernel is
installed.
There is a lot of code in fwupd that just assigns a shared object type to
a FuPlugin, and then for each device on that plugin assigns that same shared
object to each FuDevice.
Rather than proxy several kinds of information stores over two different levels
of abstraction create a 'context' which contains the shared *system* state
between the daemon, the plugins and the daemon.
This will allow us to hold other per-machine state in the future, for instance
the system battery level or AC state.