Add ready queue dequeue path in mo_task_suspend()

Previously, mo_task_suspend() only changed the task state to
TASK_SUSPENDED without removing the task from the ready queue.
As a result, suspended tasks could still be selected by the
scheduler, leading to incorrect task switching and inconsistent
queue states.

This change adds a dequeue operation to remove the corresponding
task node from its ready queue before marking it as suspended.
Additionally, the condition to detect the currently running task
has been updated: the scheduler now compares the TCB pointer
(kcb->task_current->data == task) instead of the list node
(kcb->task_current == node), since kcb->task_current now stores
a ready queue node rather than a global task list node.

If the suspended task is currently running, the CPU will yield
after the task is suspended to allow the scheduler to select
the next runnable task.

This ensures that suspended tasks are no longer visible to the
scheduler until they are resumed.

Author: vicLin8712

kernel/task.c

@@ -387,7 +387,7 @@ static void sched_enqueue_task(tcb_t *task)
 }
 
 /* Remove task from ready queue; return removed ready queue node */
-static __attribute__((unused)) list_node_t *sched_dequeue_task(tcb_t *task)
+static list_node_t *sched_dequeue_task(tcb_t *task)
 {
     if (unlikely(!task))
         return NULL;
@@ -778,8 +778,15 @@ int32_t mo_task_suspend(uint16_t id)
         return ERR_TASK_CANT_SUSPEND;
     }
 
+    /* Remove task node from ready queue if task is in ready queue
+     * (TASK_RUNNING/TASK_READY).*/
+    if (task->state == TASK_READY || task->state == TASK_RUNNING) {
+        list_node_t *rq_node = sched_dequeue_task(task);
+        free(rq_node);
+    }
+
     task->state = TASK_SUSPENDED;
-    bool is_current = (kcb->task_current == node);
+    bool is_current = (kcb->task_current->data == task);
 
     CRITICAL_LEAVE();