osbuild: don't copy in platforms.json on s390x

There are no platforms.yaml entries on that platform so we don't
create a platforms.json file inside the OSTree and we we shouldn't
try to copy the file.

src/coreos.osbuild.s390x.mpp.yaml

@@ -101,12 +101,6 @@ pipelines:
               # filesystem by OSTree (boot -> .) that makes it so that /boot paths
               # will always work.
               bootprefix: true
-      # platforms.json will live here
-      - type: org.osbuild.mkdir
-        options:
-          paths:
-            - path: /boot/coreos
-              mode: 493
       - type: org.osbuild.ignition
       # Deploy via container if we have a container ociarchive, else from repo.
       - mpp-if: ociarchive != ''
@@ -188,21 +182,6 @@ pipelines:
             ref: ostree/1/1/0
             osname:
               mpp-format-string: '{osname}'
-      # Copy in the platforms.json that was baked into the OSTree into /boot
-      # so tools like coreos-installer can use the information.
-      - type: org.osbuild.copy
-        options:
-          paths:
-            - from: tree:///usr/share/coreos-assembler/platforms.json
-              to: tree:///boot/coreos/platforms.json
-        mounts:
-          - name: ostree.deployment
-            type: org.osbuild.ostree.deployment
-            options:
-              deployment:
-                ref: ostree/1/1/0
-                osname:
-                  mpp-format-string: '{osname}'
   - name: raw-image
     stages:
       - type: org.osbuild.truncate