sysctl extern cleanup: rtmutex

Extern declarations in sysctl.c should be moved to their own header file,
and then include them in relavant .c files.

Move max_lock_depth extern declaration to linux/rtmutex.h

Signed-off-by: Dave Young <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/rtmutex.h

···
 #include <linux/plist.h>
 #include <linux/spinlock_types.h>
 
+extern int max_lock_depth; /* for sysctl */
+
 /**
  * The rt_mutex structure
  *

kernel/sysctl.c

···
 #ifdef CONFIG_BSD_PROCESS_ACCT
 #include <linux/acct.h>
 #endif
+#ifdef CONFIG_RT_MUTEXES
+#include <linux/rtmutex.h>
+#endif
 #ifdef CONFIG_CHR_DEV_SG
 #include <scsi/sg.h>
 #endif
···
 #endif
 
 extern struct ratelimit_state printk_ratelimit_state;
-
-#ifdef CONFIG_RT_MUTEXES
-extern int max_lock_depth;
-#endif
 
 #ifdef CONFIG_PROC_SYSCTL
 static int proc_do_cad_pid(struct ctl_table *table, int write,