Exclude cn88xx CPU for RHEL9
Both penguin-valkre and Gigabyte R120/R270 systems panic in rhel9, these systems are based on the original ThunderX (cn88xx) CPU which is unsupported in RHEL9
Both penguin-valkre and Gigabyte R120/R270 systems panic in rhel9, these systems are based on the original ThunderX (cn88xx) CPU which is unsupported in RHEL9