[SPARC64]: Make HAVE_DEC_LOCK depend upon DEBUG_SPINLOCK.

arch/sparc64/Kconfig

@@ -209,10 +209,6 @@ config HOTPLUG
 	  to use devices as you hotplug them.
 
 # Global things across all Sun machines.
-config HAVE_DEC_LOCK
-	bool
-	default y
-
 config RWSEM_GENERIC_SPINLOCK
 	bool
 
@@ -925,6 +921,14 @@ config DEBUG_SPINLOCK
 	  best used in conjunction with the NMI watchdog so that spinlock
 	  deadlocks are also debuggable.
 
+# We have a custom atomic_dec_and_lock() implementation but it's not
+# compatible with spinlock debugging so we need to fall back on
+# the generic version in that case.
+config HAVE_DEC_LOCK
+	bool
+	depends on !DEBUG_SPINLOCK
+	default y
+
 config DEBUG_SPINLOCK_SLEEP
 	bool "Sleep-inside-spinlock checking"
 	help