lockdep: Fix lockdep_no_validate against IRQ states

Thomas noticed that a lock marked with lockdep_set_novalidate_class()
will still trigger warnings for IRQ inversions. Cure this by skipping
those when marking irq state.

Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-2dp5vmpsxeraqm42kgww6ge2@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 298c927..628276d 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2468,6 +2468,9 @@
 
 		BUG_ON(usage_bit >= LOCK_USAGE_STATES);
 
+		if (hlock_class(hlock)->key == &__lockdep_no_validate__)
+			continue;
+
 		if (!mark_lock(curr, hlock, usage_bit))
 			return 0;
 	}