Fix UP non-preempt build for kernel lock changes.

Duh. I had tested every "interesting" combination of SMP and PREEMPT,
but the _trivial_ one was broken ;)

include/linux/smp_lock.h

@@ -47,7 +47,7 @@ extern void __lockfunc unlock_kernel(void)	__releases(kernel_lock);
 #define lock_kernel()				do { } while(0)
 #define unlock_kernel()				do { } while(0)
 #define release_kernel_lock(task)		do { } while(0)
-#define reacquire_kernel_lock(task)		do { } while(0)
+#define reacquire_kernel_lock(task)		0
 #define kernel_locked()				1
 
 #endif /* CONFIG_LOCK_KERNEL */