fixup: pty: possible memory leaking on close()

The ref_count of the vnode is NOT bound to the resource reference counts
of the ptm device created by opening `dev/ptmx`, so the conditional
release of resource may end up by memory leaking if the multiple user
have open the `dev/ptmx`.

Changes:

- Removed conditional branch on recycling resource

Signed-off-by: Shell <smokewood@qq.com>

components/lwp/terminal/tty_ptmx.c

@@ -27,7 +27,6 @@ static int ptm_fops_open(struct dfs_file *file)
     rt_uint32_t oflags = file->flags;
     rt_thread_t cur_thr = rt_thread_self();
 
-    /* we don't check refcnt because each open will create a new device */
     if (file->vnode && file->vnode->data)
     {
         /**
@@ -61,18 +60,11 @@ static int ptm_fops_close(struct dfs_file *file)
     rt_device_t device;
 
     if (file->data)
-    {
-        if (file->vnode->ref_count != 1)
-        {
-            rc = 0;
-        }
-        else
     {
         device = (rt_device_t)file->data;
         tp = rt_container_of(device, struct lwp_tty, parent);
         rc = bsd_ptsdev_methods.fo_close(tp, rt_thread_self());
     }
-    }
     else
     {
         rc = -EINVAL;