elfcore.h : Fix UML build breakage

Commit a65e7bf broke the UML build with
the following error -

  In file included from fs/proc/kcore.c:17:
  include/linux/elfcore.h: In function 'elf_core_copy_task_regs':
  include/linux/elfcore.h:129: error: implicit declaration of function 'task_pt_regs'

Fix this by restoring the previous behavior of returning 0 for all arches
like UML that don't define task_pt_regs.

Signed-off-by: Parag Warudkar <parag.lkml@gmail.com>
Acked-by: Amerigo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/elfcore.h

@@ -122,10 +122,9 @@ static inline void elf_core_copy_kernel_regs(elf_gregset_t *elfregs, struct pt_r
 
 static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t* elfregs)
 {
-#ifdef ELF_CORE_COPY_TASK_REGS
-
+#if defined (ELF_CORE_COPY_TASK_REGS)
 	return ELF_CORE_COPY_TASK_REGS(t, elfregs);
-#else
+#elif defined (task_pt_regs)
 	elf_core_copy_regs(elfregs, task_pt_regs(t));
 #endif
 	return 0;