Refa: PARALLEL_DEVICES is a static parameter. (#6168)

### What problem does this PR solve?


### Type of change

- [x] Refactoring

deepdoc/vision/t_ocr.py

@@ -34,15 +34,15 @@ import trio
 os.environ['CUDA_VISIBLE_DEVICES'] = '0' #1 gpu
 # os.environ['CUDA_VISIBLE_DEVICES'] = '' #cpu
 
+
 def main(args):
     import torch.cuda
 
     cuda_devices = torch.cuda.device_count()
     limiter = [trio.CapacityLimiter(1) for _ in range(cuda_devices)] if cuda_devices > 1 else None
-    ocr = OCR(parallel_devices = cuda_devices)
+    ocr = OCR()
     images, outputs = init_in_out(args)
 
-
     def __ocr(i, id, img):
         print("Task {} start".format(i))
         bxs = ocr(np.array(img), id)