m68k: Revive _TIF_* masks

While the core m68k code does not use the _TIF_* masks anymore, there
exists generic code that relies on their presence.  Fortunately none of
that code is used on m68k, currently.

Re-add the various _TIF_* masks, which were removed in commit
cddafa35 ("m68k/m68knommu: merge MMU and non-MMU
thread_info.h"), to avoid future nasty surprises.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200826122923.22821-1-geert@linux-m68k.org

arch/m68k/include/asm/thread_info.h

@@ -68,4 +68,12 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_MEMDIE		16	/* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK	18	/* restore signal mask in do_signal */
 
+#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+#define _TIF_DELAYED_TRACE	(1 << TIF_DELAYED_TRACE)
+#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
+#define _TIF_MEMDIE		(1 << TIF_MEMDIE)
+#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
+
 #endif	/* _ASM_M68K_THREAD_INFO_H */