selftests/powerpc: Fix resource leaks
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.86 by commit 8de2c29db68b3d7e4cd2661059085b14c450763a, it was introduced in version v4.2 by commit ebd5858c904b1c795f1511758a7ac043afd44438. For more details please see the references link.