redhat: Change gating configuration for RT kernel

RT kernel needs only to pass an additional manual gating step.

Change gating configuration to that end.

Signed-off-by: Juri Lelli <juri.lelli@redhat.com>

redhat/gating.yaml

@@ -3,7 +3,4 @@ product_versions:
   - rhel-9
 decision_context: osci_compose_gate
 rules:
-  - !PassingTestCaseRule {test_case_name: cki.tier1-aarch64.functional}
-  - !PassingTestCaseRule {test_case_name: cki.tier1-ppc64le.functional}
-  - !PassingTestCaseRule {test_case_name: cki.tier1-s390x.functional}
-  - !PassingTestCaseRule {test_case_name: cki.tier1-x86_64.functional}
+  - !PassingTestCaseRule {test_case_name: manual.sst_kernel_maintainers.kernel-rt.final}