Reboot <args> is stored in /run/systemd/reboot-param. Copy to
fw_setenv bootargs_mode for pickup by u-boot.

Since v240 gets reset by SuccessAction=reboot-force.
https://github.com/systemd/systemd/issues/11828


Fix that by reverting.

Signed-off-by: Ferry Toth <ftoth@exalondelft.nl>