LU-18784 dkms: add systemd check for dkms-debs

LU-18784 dkms: add systemd check for dkms-debs

The lustre-client-utils packaging of:
  /usr/lib/systemd/system/lnet.service
is conditional upon the presence of systemd.

Include the check when building the dkms-debs target.

Test-Parameters: trivial testgroup=full-dkms
HPE-bug-id: LUS-12776
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I583338cda8fd49cbb845ed71bb2cb34a1db3cc74
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58341
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Caleb Carlson <caleb.carlson@hpe.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>