arch: remove unused macro/function thread_saved_pc()

The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d55977 ("sched/core: Remove pointless printout in
sched_show_task()").  Remove the implementations as well.

Some architectures use thread_saved_pc() in their arch-specific code.
Leave their thread_saved_pc() intact.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/include/asm/processor-generic.h

@@ -58,8 +58,6 @@ static inline void release_thread(struct task_struct *task)
 {
 }
 
-extern unsigned long thread_saved_pc(struct task_struct *t);
-
 static inline void mm_copy_segments(struct mm_struct *from_mm,
 				    struct mm_struct *new_mm)
 {