procfs: procfs_opendir should return fail if can't match

Signed-off-by: ligd <liguiding1@xiaomi.com>

fs/procfs/fs_procfs.c

@@ -664,6 +664,11 @@ static int procfs_opendir(FAR struct inode *mountpt, FAR const char *relpath,
               break;
             }
         }
+
+      if (x == g_procfs_entrycount)
+        {
+          return -ENOENT;
+        }
     }
 
   dir->u.procfs = priv;