ci: remove autotune dependency from build:benchmark

The workaround needed to make this work is has major disadvantages,
and our current workflow does not make use of this dependency anyway
(Currently the generated configs are checked into the repository, so
the CI would run the benchmarks on them on the next push to the
merge-request).

When we improve automation around autotuning this could be implemented
with conditional jobs, but lets just drop the dependency for now.

.gitlab-ci.yml

@@ -230,9 +230,7 @@ build:package:
 
 build:benchmark:
   stage: build
-  needs:
-    - job: "autotune:generate-config"
-      optional: true
+  needs: []
   tags:
     - rocm-build
   extends: