lockup_detector: Don't enable the lockup detector by default

The lockup detector is a new feature that now involves the
nmi watchdog. Drop the default y and let the user choose.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>

lib/Kconfig.debug

@@ -155,7 +155,6 @@ config DEBUG_SHIRQ
 config LOCKUP_DETECTOR
 	bool "Detect Hard and Soft Lockups"
 	depends on DEBUG_KERNEL && !S390
-	default y
 	help
 	  Say Y here to enable the kernel to act as a watchdog to detect
 	  hard and soft lockups.