The sample install-config.yaml[1] for agent based installation needs an update.
As per documentation[2] there is a list of supported architecture given. However in the [1] there is no example mentioned as mentioned in the [3]

- [1] https://docs.openshift.com/container-platform/4.18/installing/installing_with_agent_based_installer/preparing-to-install-with-agent-based-installer.html#installation-bare-metal-agent-installer-config-yaml_preparing-to-install-with-agent-based-installer:~:text=Configuring%20network%20bonding-,Sample%20install%2Dconfig.yaml%20file%20for%20bare%20metal,-You%20can%20customize


-  [2] https://docs.openshift.com/container-platform/4.18/installing/installing_with_agent_based_installer/preparing-to-install-with-agent-based-installer.html#:~:text=Agent%2Dbased%20Installer%20supported%20architectures

- [3] https://docs.openshift.com/container-platform/4.18/installing/installing_ibm_power/installing-restricted-networks-ibm-power.html#installation-bare-metal-config-yaml_installing-restricted-networks-ibm-power:~:text=replicas%3A%200-,architecture,-%3A%20ppc64le%0AcontrolPlane

    <=4.18

    1.
    2.
    3.
    

apiVersion: v1
baseDomain: example.com 
compute: 
- name: worker
  replicas: 0 
controlPlane: 
  name: master
  replicas: 1 

documentation[2] should have following update:

apiVersion: v1
baseDomain: example.com 
compute: 
- name: worker
  replicas: 0 
  architecture: <ppc64le>  <----------
controlPlane: 
  name: master
  replicas: 1 
  architecture: <ppc64le>  <----------