sched: Constify function scope static struct sched_param usage

Function-scope statics are discouraged because they are
easily overlooked and can cause subtle bugs/races due to
their global (non-SMP safe) nature.

Linus noticed that we did this for sched_param - at minimum
make the const.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: Message-ID: <AANLkTinotRxScOHEb0HgFgSpGPkq_6jKTv5CfvnQM=ee@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 91a5fa2..0caa59f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -577,7 +577,7 @@
  */
 static int irq_thread(void *data)
 {
-	static struct sched_param param = {
+	static const struct sched_param param = {
 		.sched_priority = MAX_USER_RT_PRIO/2,
 	};
 	struct irqaction *action = data;