csky: remove unusued thread_saved_pc and *_segments functions/macros

These are used nowhere in the tree (except for some architectures which
define them for their own use) and were already removed for other
architectures in:

commit 6474924e ("arch: remove unused macro/function thread_saved_pc()")
commit c17c0204 ("arch: remove unused *_segments() macros/functions")

Remove them from arch/csky as well.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>

arch/csky/include/asm/processor.h

@@ -82,12 +82,6 @@ static inline void release_thread(struct task_struct *dead_task)
 
 extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
-#define copy_segments(tsk, mm)		do { } while (0)
-#define release_segments(mm)		do { } while (0)
-#define forget_segments()		do { } while (0)
-
-extern unsigned long thread_saved_pc(struct task_struct *tsk);
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->pc)

arch/csky/kernel/process.c

@@ -30,16 +30,6 @@ asmlinkage void ret_from_kernel_thread(void);
  */
 void flush_thread(void){}
 
-/*
- * Return saved PC from a blocked thread
- */
-unsigned long thread_saved_pc(struct task_struct *tsk)
-{
-	struct switch_stack *sw = (struct switch_stack *)tsk->thread.sp;
-
-	return sw->r15;
-}
-
 int copy_thread_tls(unsigned long clone_flags,
 		unsigned long usp,
 		unsigned long kthread_arg,