systemd: Correct path returned in sd_path_lookup()

In oe-core, sysusers.d/sysctl.d/binfmt.d/modules-load.d are still kept
under /usr/lib instead of /lib changed in systemd v246. This patch
corrects the SD_PATH_{SYSUSERS,SYSCTL,BINFMT,MODULES_LOAD} returned
in sd_path_lookup() back to the /usr/lib ones.

Also updates the patch description and upstream status.

Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>