iscsi: do iscsi_firmware regardless of network

Do the iscsi_firmware iscsistart at least once, even if the network is
not up, to activate offload HBA iSCSI.

https://bugzilla.redhat.com/show_bug.cgi?id=1031160
dracut-lib/wait_for_dev(): prevent systemd daemon-reload

prevent a systemd daemon-reload, if it is not necessary to do.