pids: Move task_pid_type into sched/signal.h

The function is general and inline so there is no need
to hide it inside of exit.c
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

include/linux/sched/signal.h

@@ -556,6 +556,14 @@ extern bool current_is_single_threaded(void);
 typedef int (*proc_visitor)(struct task_struct *p, void *data);
 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
 
+static inline
+struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+{
+	if (type != PIDTYPE_PID)
+		task = task->group_leader;
+	return task->pids[type].pid;
+}
+
 static inline int get_nr_threads(struct task_struct *tsk)
 {
 	return tsk->signal->nr_threads;

kernel/exit.c

@@ -1001,14 +1001,6 @@ struct wait_opts {
 	int			notask_error;
 };
 
-static inline
-struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
-{
-	if (type != PIDTYPE_PID)
-		task = task->group_leader;
-	return task->pids[type].pid;
-}
-
 static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
 {
 	return	wo->wo_type == PIDTYPE_MAX ||