lockdep_sys_exit can be called from assembler code, so make it
asmlinkage.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391845930-28580-5-git-send-email-ak@linux.intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>