From peers working with CentOS on Power8,
/"I am trying to install OPAL-PRD on cent-os. Do you know where to get opal-prd package ?"/
Presently opal-prd is not available in the CentOS repos or in EPEL, but is expected in a future release of RHEL.
In the meantime, it is possible to build the rpm from source and install on CentOS.
Latest source rpm : https://hegdevasant.fedorapeople.org/opal-prd/v5/opal-prd-5.1.13-1.fc22.src....
Thanks to Vasant Hegde for pointer to files.