fix v2_det_pact oom

test_tipc/configs/ch_PP-OCRv2_det_PACT/train_infer_python.txt

@@ -6,7 +6,7 @@ Global.use_gpu:True|True
 Global.auto_cast:fp32
 Global.epoch_num:lite_train_lite_infer=1|whole_train_whole_infer=500
 Global.save_model_dir:./output/
-Train.loader.batch_size_per_card:lite_train_lite_infer=2|whole_train_whole_infer=4
+Train.loader.batch_size_per_card:lite_train_lite_infer=1|whole_train_whole_infer=4
 Global.pretrained_model:null
 train_model_name:latest
 train_infer_img_dir:./train_data/icdar2015/text_localization/ch4_test_images/