sched/debug: Don't dump sched debug info in SysRq-W

sysrq_sched_debug_show() can dump a lot of information.  Don't print out
all that if we're just trying to get a list of blocked tasks (SysRq-W).
The information is still accessible with SysRq-T.
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459777322-30902-1-git-send-email-rabin.vincent@axis.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -5050,6 +5050,7 @@ void show_state_filter(unsigned long state_filter)
 	touch_all_softlockup_watchdogs();
 
 #ifdef CONFIG_SCHED_DEBUG
+	if (!state_filter)
 		sysrq_sched_debug_show();
 #endif
 	rcu_read_unlock();