OOT Kernel modules distrbuted as tar.xz (like for dpdk kni kmods) requires the xz for tar to uncompress it. The same package requires the cmp command (which is part of diffutils) to compile the kmod.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: OpenShift Container Platform 4.8.2 bug fix and security update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2021:2438