Multipath day1 not working on s390x

Description of problem:
When enabling multipath during firstboot with ignition-kargs, it fails and boots into the emergency shell instead.

Version-Release number of selected component (if applicable):
4.9

How reproducible:
Append multipath kargs through ignition during firstboot

Steps to Reproduce:
1. Create ignition with multipath kargs
2. Install rhcos with ignition-file
3.

Actual results:
Boot into emergency shell

Expected results:
Boot rhcos with multipath from day1

Additional info:
The Problem is a missing zipl helper script in the initramfs, preventing zipl to recognize the device-mapper and running correctly. The fix is already upstream.