[scripts] drop rc-update calls, openrc is no longer supported

scripts/mkloopcard_chroot.include

@@ -57,10 +57,8 @@ setup_bootfs_fstab() {
 
 setup_boot() {
     sd_enable sshd
-    rc-update add sshd default
     sd_enable vixie-cron
     sd_enable NetworkManager
-    rc-update add NetworkManager default
     eselect uimage set 1
 }