mutex: Move ww_mutex definitions to ww_mutex.h

Move the definitions for wound/wait mutexes out to a separate
header, ww_mutex.h. This reduces clutter in mutex.h, and
increases readability.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Dave Airlie <airlied@gmail.com>
Link: http://lkml.kernel.org/r/51D675DC.3000907@canonical.com
[ Tidied up the code a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/reservation.h

@@ -39,7 +39,7 @@
 #ifndef _LINUX_RESERVATION_H
 #define _LINUX_RESERVATION_H
 
-#include <linux/mutex.h>
+#include <linux/ww_mutex.h>
 
 extern struct ww_class reservation_ww_class;
 

kernel/mutex.c

@@ -18,6 +18,7 @@
  * Also see Documentation/mutex-design.txt.
  */
 #include <linux/mutex.h>
+#include <linux/ww_mutex.h>
 #include <linux/sched.h>
 #include <linux/sched/rt.h>
 #include <linux/export.h>

lib/locking-selftest.c

@@ -12,6 +12,7 @@
  */
 #include <linux/rwsem.h>
 #include <linux/mutex.h>
+#include <linux/ww_mutex.h>
 #include <linux/sched.h>
 #include <linux/delay.h>
 #include <linux/lockdep.h>