tools/liblockdep: Correct macro for WARN

As Peter Zijlstra pointed out, the varargs for WARN() are
optional, so we need to correctly handle the case where they
don't exist.

This would cause a compilation error.

Signed-off-by: Sasha Levin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

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

···
 #define WARN_ON(x) (x)
 #define WARN_ON_ONCE(x) (x)
 #define likely(x) (x)
-#define WARN(x, y, z) (x)
+#define WARN(x, y...) (x)
 #define uninitialized_var(x) x
 #define __init
 #define noinline