autoconf: add kernel module to the summary

autoconf: add kernel module to the summary

Add the kernel module to the list of optional build items in the
configure summary to indicate whether the kernel module build is
enabled.

Reviewed-on: https://gerrit.openafs.org/13005
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 3d3e7bc51aaf39b5ca04bfd36ff9017ab0622057)

Change-Id: I842752bb12b09fdcab6bfb341673bff3528f3880
Reviewed-on: https://gerrit.openafs.org/13112
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Joe Gorse <jhgorse@gmail.com>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>