upeksonly: use fpi_std_sq_dev() and fpi_mean_sq_diff_norm()
upeksonly: use fpi_std_sq_dev() and fpi_mean_sq_diff_norm()

Use fpi_mean_sq_diff_norm() for blank line detection and
fpi_mean_sq_diff_norm() for duplicate line detection.
Fixes finger presence and removal detection.

anarsoul/libfprint,iafilatov/libfprint,anarsoul/libfprint