Pass the struct fp_dev and user_data to fpi_ssm callbacks, so that we
might be able to get rid of the fpi_ssm_get_user_data(), and
fpi_ssm_get_dev() as most drivers just get those from the ssm anyway
in their callbacks.
Remove all the headers already included through "fp_internal.h" such as
<libusb.h> and <errno.h>, include "assembling.h" and "driver_ids.h" there
as well to avoid doing it in (almost) every driver.
Imaging drivers aren't allowed to change number of enroll stages anymore,
all that imaging driver does is providing image to the upper layer.
Upper layer decides if it needs more scans.
ID is just a some magic number to make fingerprint from one scanner model
incompatible with another scanner model. Get rid of "magic", declare enum
and use it.
https://bugs.freedesktop.org/show_bug.cgi?id=56956