um: Get rid of thread_struct->saved_task

As we have a sane show_stack() now, we can drop
the ->saved_task hack.

Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index bbcef52..eecc414 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -82,19 +82,8 @@
 	to->thread.prev_sched = from;
 	set_current(to);
 
-	do {
-		current->thread.saved_task = NULL;
-
-		switch_threads(&from->thread.switch_buf,
-			       &to->thread.switch_buf);
-
-		arch_switch_to(current);
-
-		if (current->thread.saved_task)
-			show_regs(&(current->thread.regs));
-		to = current->thread.saved_task;
-		from = current;
-	} while (current->thread.saved_task);
+	switch_threads(&from->thread.switch_buf, &to->thread.switch_buf);
+	arch_switch_to(current);
 
 	return current->thread.prev_sched;
 }