lockdep: Provide off case for redundant_hardirqs_on increment

We forgot to provide a !CONFIG_DEBUG_LOCKDEP case for the
redundant_hardirqs_on stat handling.

Manage that in the headers with a new __debug_atomic_inc() helper.

Fixes:

	kernel/lockdep.c:2306: error: 'lockdep_stats' undeclared (first use in this function)
	kernel/lockdep.c:2306: error: (Each undeclared identifier is reported only once
	kernel/lockdep.c:2306: error: for each function it appears in.)

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 1b58a1b..9cf7985 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2303,7 +2303,7 @@
 		 * so this is racy by nature but loosing one hit
 		 * in a stat is not a big deal.
 		 */
-		this_cpu_inc(lockdep_stats.redundant_hardirqs_on);
+		__debug_atomic_inc(redundant_hardirqs_on);
 		return;
 	}
 	/* we'll do an OFF -> ON transition: */