watchdog/softlockup: Fix the SOFTLOCKUP_DETECTOR=n build

I got confused by all the various CONFIG options here about and
conflated CONFIG_LOCKUP_DETECTOR and CONFIG_SOFTLOCKUP_DETECTOR.

This results in a build failure for:

   CONFIG_LOCKUP_DETECTOR=y && CONFIG_SOFTLOCKUP_DETECTOR=n

As reported by Abdul.

Reported-and-tested-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-next <linux-next@vger.kernel.org>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: mpe <mpe@ellerman.id.au>
Cc: sachinp <sachinp@linux.vnet.ibm.com>
Cc: stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 9cf57731b63e ("watchdog/softlockup: Replace "watchdog/%u" threads with cpu_stop_work")
Link: http://lkml.kernel.org/r/20180710114210.GI2476@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/nmi.h

@@ -33,15 +33,10 @@ extern int sysctl_hardlockup_all_cpu_backtrace;
 #define sysctl_hardlockup_all_cpu_backtrace 0
 #endif /* !CONFIG_SMP */
 
-extern int lockup_detector_online_cpu(unsigned int cpu);
-extern int lockup_detector_offline_cpu(unsigned int cpu);
-
 #else /* CONFIG_LOCKUP_DETECTOR */
 static inline void lockup_detector_init(void) { }
 static inline void lockup_detector_soft_poweroff(void) { }
 static inline void lockup_detector_cleanup(void) { }
-#define lockup_detector_online_cpu	NULL
-#define lockup_detector_offline_cpu	NULL
 #endif /* !CONFIG_LOCKUP_DETECTOR */
 
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
@@ -50,12 +45,18 @@ extern void touch_softlockup_watchdog(void);
 extern void touch_softlockup_watchdog_sync(void);
 extern void touch_all_softlockup_watchdogs(void);
 extern unsigned int  softlockup_panic;
-#else
+
+extern int lockup_detector_online_cpu(unsigned int cpu);
+extern int lockup_detector_offline_cpu(unsigned int cpu);
+#else /* CONFIG_SOFTLOCKUP_DETECTOR */
 static inline void touch_softlockup_watchdog_sched(void) { }
 static inline void touch_softlockup_watchdog(void) { }
 static inline void touch_softlockup_watchdog_sync(void) { }
 static inline void touch_all_softlockup_watchdogs(void) { }
-#endif
+
+#define lockup_detector_online_cpu	NULL
+#define lockup_detector_offline_cpu	NULL
+#endif /* CONFIG_SOFTLOCKUP_DETECTOR */
 
 #ifdef CONFIG_DETECT_HUNG_TASK
 void reset_hung_task_detector(void);