wpa-supplicant: remove service templates from SYSTEMD_SERVICE

Remove service templates wpa_supplicant-nl80211@.service and
wpa_supplicant-wired@.service from SYSTEMD_SERVICE that they should NOT
be started/stopped by calling 'systemctl' in postinst and prerm scripts.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit fe9b8e50)
Signed-off-by: Steve Sakoman <steve@sakoman.com>