schedule: remove scheduler_restore()

The last user of schedule_restore() was removed in commit 4f2e381
("build: remove more XTOS left-overs"), so we can proceed it to remove
it from schedule.h interface.

This will pave way for further simplications of the schedule.h
interface now as the role of this interface is reduce to audio task
scheduling, while low-level task scheduling is done in Zephyr.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

src/include/sof/schedule/schedule.h

@@ -149,15 +149,6 @@ struct scheduler_ops {
 	 * This operation is optional.
 	 */
 	void (*scheduler_free)(void *data, uint32_t flags);
-
-	/**
-	 * Restores scheduler's resources.
-	 * @param data Private data of selected scheduler.
-	 * @return 0 if succeeded, error code otherwise.
-	 *
-	 * This operation is optional.
-	 */
-	int (*scheduler_restore)(void *data);
 };
 
 /** \brief Holds information about scheduler. */
@@ -361,24 +352,6 @@ static inline void schedule_free(uint32_t flags)
 	}
 }
 
-/** See scheduler_ops::scheduler_restore */
-static inline int schedulers_restore(void)
-{
-	struct schedulers *schedulers = *arch_schedulers_get();
-	struct schedule_data *sch;
-	struct list_item *slist;
-
-	assert(schedulers);
-
-	list_for_item(slist, &schedulers->list) {
-		sch = container_of(slist, struct schedule_data, list);
-		if (sch->ops->scheduler_restore)
-			return sch->ops->scheduler_restore(sch->data);
-	}
-
-	return 0;
-}
-
 /**
  * Initializes scheduling task.
  * @param task Task to be initialized.