sched: finalize_cancel_locked can early return

The code `SYS_SLIST_FOR_EACH_CONTAINER_SAFE` just for remove work
from `pending_cancels`.
After removing work successfully, the function can return early.
It is unnecessary to iterate continuously.

Signed-off-by: TaiJu Wu <tjwu1217@gmail.com>

kernel/work.c

@@ -141,9 +141,9 @@ static void finalize_cancel_locked(struct k_work *work)
 		if (wc->work == work) {
 			sys_slist_remove(&pending_cancels, prev, &wc->node);
 			k_sem_give(&wc->sem);
-		} else {
-			prev = &wc->node;
+			break;
 		}
+		prev = &wc->node;
 	}
 }