perf bench futex: Fix memory leak of perfcpumap__new()
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 v5.10.82 by commit 2ada5c0877f4aa9b0749e7777557d9a5d2973082, it was introduced in version v5.4 by commit 9c3516d1b850ea938b074df33e4c86d721c77720. For more details please see the references link.