Enable buildroot repos for rhel-8 releases
Based on discussion on https://gitlab.com/cki-project/kernel-tests/-/merge_requests/789 it would be better for tests that buildroot repos are enabled.
They need to be enabled on all RHEL-8 trees:
rhel8
rhel8-rt
rhel81-z
rhel82-z
rhel82-z-rt
rhel83-z
rhel83-z-rt
Edited by Bruno Goncalves