Allows drivers to define more fine grained features for devices, not
strictly depending on assumptions we can make depending on the
implemented vfuncs.
We keep this per class but could be in theory moved to each instance.
In any case, added an utility function to initialize it in the way we
can ensure that we've a consistent way for setting them across all the
devices.
It is a good idea to report match results early, to e.g. log in a user
immediately even if more device interaction is needed. Add new _full
variants for the verify/identify functions, with a corresponding
callback. Also move driver result reporting into new
fpi_device_{identify,verify}_report functions and remove the reporting
from the fpi_device_{identify,verify}_complete calls.
Basic updates to code is done in places. Only the upekts driver is
actually modified from a behaviour point of view. The image driver code
should be restructured quite a bit to split the reporting and only
report completion after device deactivation. This should simplifiy the
code quite a bit again.
