[S390] fix _TIF_SINGLE_STEP definition

_TIF_SINGLE_STEP is incorrectly defined as 1<<TIF_FREEZE.  Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/thread_info.h

@@ -117,7 +117,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SIE		(1<<TIF_SIE)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_31BIT		(1<<TIF_31BIT)
-#define _TIF_SINGLE_STEP	(1<<TIF_FREEZE)
+#define _TIF_SINGLE_STEP	(1<<TIF_SINGLE_STEP)
 #define _TIF_FREEZE		(1<<TIF_FREEZE)
 
 #ifdef CONFIG_64BIT