s390: remove unused TASK_SIZE_OF

This macro isn't used in Linux sched, now. Delete in
include/linux/sched.h and arch's include/asm.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211228064730.2882351-6-guoren@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Author: guoren83

arch/s390/include/asm/processor.h

@@ -88,11 +88,10 @@ extern void __bpon(void);
  * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit.
  */
 
-#define TASK_SIZE_OF(tsk)	(test_tsk_thread_flag(tsk, TIF_31BIT) ? \
+#define TASK_SIZE		(test_thread_flag(TIF_31BIT) ? \
 					_REGION3_SIZE : TASK_SIZE_MAX)
 #define TASK_UNMAPPED_BASE	(test_thread_flag(TIF_31BIT) ? \
 					(_REGION3_SIZE >> 1) : (_REGION2_SIZE >> 1))
-#define TASK_SIZE		TASK_SIZE_OF(current)
 #define TASK_SIZE_MAX		(-PAGE_SIZE)
 
 #define STACK_TOP		(test_thread_flag(TIF_31BIT) ? \