remove critical area operation in shell task to aviod system lag at xidatong-arm board from Wang_weigen

it is OK

Ubiquitous/XiZi/tool/shell/letter-shell/shell.c

@@ -1649,15 +1649,12 @@ void shellTask(void *param)
         if (shell->read) {
             memset(data, 0, KEY_LENGTH);
             data_len = 0;
-            x_base lock;
 
             data_len = shell->read(data);
             if(data_len > 0) {
-                int lock = CriticalAreaLock();
                 for (i = 0; i < data_len; i++) {
                     shellHandler(shell, data[i]);
                 }
-                CriticalAreaUnLock(lock);
             }
         }
     }