sched: fix memory leak in a failure path

Impact: fix rare memory leak in the sched-domains manual reconfiguration code

In the failure path, rd is not attached to a sched domain,
so it causes a leak.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -7676,6 +7676,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
 error:
 	free_sched_groups(cpu_map, tmpmask);
 	SCHED_CPUMASK_FREE((void *)allmasks);
+	kfree(rd);
 	return -ENOMEM;
 #endif
 }