This is a clone of issue OCPBUGS-19092. The following is the description of the original issue:
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When creating an Agent ISO for OCI, we should add the kernel argument console=ttyS0 to the ISO/PXE kargs.

CoreOS does not include a console arg by default when using metal as the platform because different hardware has different consoles and specifying one can cause booting to fail on some, but it does on many cloud platforms. Since we know when the user is definitely using OCI (there are validations in assisted that ensure it) and we know the correct settings for OCI, we should set them up automatically.