CI: remove utility tasks

These tasks made some limited sense when there was only one runner, but
in a setup where there are N runners they arere pretty useless as you
can't control which runner is executing the jobs.

Disk usage should be managed out-of-band, so delete the jobs.

Signed-off-by: Ross Burton <ross.burton@arm.com>

.gitlab-ci.yml

@@ -216,54 +216,3 @@ tc1:
 
 toolchains:
   extends: .build
-
-#
-# Utility tasks, not executed automatically
-#
-
-delete-dl-dir:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - rm -rf $DL_DIR/*
-
-delete-repo-dir:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - rm -rf $KAS_REPO_REF_DIR/*
-
-# Delete all sstate
-delete-sstate:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - rm -rf $SSTATE_DIR/*
-
-delete-toolchains:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - rm -rf $TOOLCHAIN_DIR/*
-
-# Wipe out old sstate
-prune-sstate:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - du -h -s $SSTATE_DIR
-    - find $SSTATE_DIR -type f -atime +30 -delete
-    - du -h -s $SSTATE_DIR
-
-# Report on disk usage
-usage:
-  extends: .setup
-  stage: prep
-  when: manual
-  script:
-    - du -h -s $DL_DIR $SSTATE_DIR $KAS_REPO_REF_DIR $TOOLCHAIN_DIR