perf sched: Free thread->priv using priv_destructor

In many perf sched subcommand saves priv data structure in the thread
but it forgot to free them.  As it's an opaque type with 'void *', it
needs to register that knows how to free the data.  In this case, just
regular 'free()' is fine.

Fixes: 04cb4fc4d4 ("perf thread: Allow tools to register a thread->priv destructor")
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250703014942.1369397-3-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/builtin-sched.c

@@ -3898,6 +3898,8 @@ int cmd_sched(int argc, const char **argv)
 	if (!argc)
 		usage_with_options(sched_usage, sched_options);
 
+	thread__set_priv_destructor(free);
+
 	/*
 	 * Aliased to 'perf script' for now:
 	 */