kernel/watchdog: remove unused declaration

Patch series "Improve watchdog config for arch watchdogs", v4.

A series to make the hardlockup watchdog more easily replaceable by arch
code.  The last patch provides some justification for why we want to do
this (existing sparc watchdog is another that could benefit).

This patch (of 5):

Remove unused declaration.

Link: http://lkml.kernel.org/r/20170616065715.18390-2-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com>	[sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/nmi.h

@@ -12,9 +12,6 @@ extern void touch_softlockup_watchdog_sched(void);
 extern void touch_softlockup_watchdog(void);
 extern void touch_softlockup_watchdog_sync(void);
 extern void touch_all_softlockup_watchdogs(void);
-extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
-				  void __user *buffer,
-				  size_t *lenp, loff_t *ppos);
 extern unsigned int  softlockup_panic;
 extern unsigned int  hardlockup_panic;
 void lockup_detector_init(void);