um: bury unused _TIF_RESTORE_SIGMASK

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/um/include/asm/thread_info.h

@@ -79,6 +79,5 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 #define _TIF_MEMDIE		(1 << TIF_MEMDIE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
-#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
 
 #endif