Description of problem:
The newly split-out systemd-boot-unsigned subpackage is required by systemd-udev, but missing on ppc64le, causing any builds requiring kdelibs or udisks2 to fail.

Version-Release number of selected component (if applicable):
systemd-251.13-5.fc37

How reproducible:
Always.

Steps to Reproduce:
1. Try rebuilding current f37 branch of chemtool on ppc64le

Actual results:
mock fails with:
DEBUG util.py:445:  Package make-1:4.3-11.fc37.ppc64le is already installed.
DEBUG util.py:443:  Error: 
DEBUG util.py:443:   Problem: package kdelibs-6:4.14.38-35.fc37.ppc64le requires udisks2, but none of the providers can be installed
DEBUG util.py:443:    - package udisks2-2.9.4-5.fc37.ppc64le requires udev >= 208, but none of the providers can be installed
DEBUG util.py:443:    - conflicting requests
DEBUG util.py:443:    - nothing provides systemd-boot-unsigned(ppc-64) = 251.13-5.fc37 needed by systemd-udev-251.13-5.fc37.ppc64le

Expected results:
Successful build.

Additional info:
This commit added the Requires:
https://src.fedoraproject.org/rpms/systemd/c/bfed7e5c115dce95fc1fd0b0d5130975f2b0702d?branch=f37
but it did not make them conditional under %if 0%{?have_gnu_efi}.