perf hist: Fix memory leak of a perf_hpp_fmt
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 v5.15.7 by commit 5b5c6f57a1f81499db4c8ea597898cb1b87de0b6. For more details please see the references link.