thread: move thread awaken functionality to a dedicated function

sched/thread.c

@@ -127,6 +127,17 @@ int thread_priority(struct thread *thr)
 	return thr->tr_prio;
 }
 
+void thread_awaken(struct thread *thr)
+{
+	struct runqueue *rq = thr->tr_rq;
+	if (!rq) {
+		rq = cpu_rq(this_cpu());
+	}
+
+	thr->tr_state = THREAD_READY;
+	rq_enqueue(rq, thr);
+}
+
 struct thread *create_kernel_thread(void (*fn)(void))
 {
 	struct task *kernel = kernel_task();