[S390] remove superfluous TIF_USEDFPU bit

The TIF_USEDFPU bit is always 0 for s390 and it is not tested anywhere.
Remove the bit. At the same time remove the calls to clear_used_math()
as well. The PF_USED_MATH bit is never set for s390 either.

Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/thread_info.h

···
 #define TIF_SYSCALL_AUDIT	9	/* syscall auditing active */
 #define TIF_SECCOMP		10	/* secure computing */
 #define TIF_SYSCALL_TRACEPOINT	11	/* syscall tracepoint instrumentation */
-#define TIF_USEDFPU		16	/* FPU was used by this task this quantum (SMP) */
-#define TIF_POLLING_NRFLAG	17	/* true if poll_idle() is polling 
+#define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling
 					   TIF_NEED_RESCHED */
-#define TIF_31BIT		18	/* 32bit process */ 
-#define TIF_MEMDIE		19
-#define TIF_RESTORE_SIGMASK	20	/* restore signal mask in do_signal() */
-#define TIF_FREEZE		21	/* thread is freezing for suspend */
+#define TIF_31BIT		17	/* 32bit process */
+#define TIF_MEMDIE		18
+#define TIF_RESTORE_SIGMASK	19	/* restore signal mask in do_signal() */
+#define TIF_FREEZE		20	/* thread is freezing for suspend */
 
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
···
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP		(1<<TIF_SECCOMP)
 #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
-#define _TIF_USEDFPU		(1<<TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_31BIT		(1<<TIF_31BIT)
 #define _TIF_FREEZE		(1<<TIF_FREEZE)

arch/s390/kernel/process.c

···
 
 void flush_thread(void)
 {
-	clear_used_math();
-	clear_tsk_thread_flag(current, TIF_USEDFPU);
 }
 
 void release_thread(struct task_struct *dead_task)

arch/s390/kernel/setup.c

···
          */
 	get_cpu_id(&S390_lowcore.cpu_id);
 
-        /*
-         * Force FPU initialization:
-         */
-        clear_thread_flag(TIF_USEDFPU);
-        clear_used_math();
-
 	atomic_inc(&init_mm.mm_count);
 	current->active_mm = &init_mm;
 	BUG_ON(current->mm);