sched: do not set softirqs to nice +19

do not set softirqs to nice +19. _If_ for whatever reason
we missed to process some high-prio softirq and woke up
ksoftirqd, we should give it a fair chance to actually
get some work done, even if the system is under load.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/softirq.c

@@ -488,7 +488,6 @@ void __init softirq_init(void)
 
 static int ksoftirqd(void * __bind_cpu)
 {
-	set_user_nice(current, 19);
 	current->flags |= PF_NOFREEZE;
 
 	set_current_state(TASK_INTERRUPTIBLE);