Booting on s390x is a little bit different compared to other architectures.
Let's add some information for people who are not yet used to this.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20200806150507.12073-1-thuth@redhat.com>
[CH: minor wording tweaks]
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
