tools/lib/lockdep: Include err.h

This provides PTR_ERR() now used by lockdep.
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: a.p.zijlstra@chello.nl
Cc: ben@decadent.org.uk
Link: http://lkml.kernel.org/r/20170525130005.5947-18-alexander.levin@verizon.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

tools/lib/lockdep/uinclude/linux/kernel.h

@@ -6,6 +6,7 @@
 #include <linux/rcu.h>
 #include <linux/hardirq.h>
 #include <linux/kern_levels.h>
+#include <linux/err.h>
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))