Mutex compilation error

[David Howells <dhowells@redhat.com>]

Hi Ingo,

I've found a compilation error in mutexes when using the null variety:

	In file included from kernel/mutex-debug.c:25:
	kernel/mutex-debug.h:23:1: warning: "__IP__" redefined
	In file included from include/asm/mutex.h:9,
			 from kernel/mutex-debug.c:23:
	include/asm-generic/mutex-null.h:15:1: warning: this is the location of the previous definition

It seems that mutex-null.h defined __IP__ before mutex-debug.h because in
mutex-debug.c:

	#include <asm/mutex.h>

	#include "mutex-debug.h"

is the ordering of the includes.

Whilst mutex-null.h defends against multiple inclusions of __IP__,
mutex-debug.h does not.

David