!8654 fix train failed of resnet_thor

From: @wangmin0104
Reviewed-by: 
Signed-off-by:

model_zoo/official/cv/resnet_thor/src/model_thor.py

@@ -118,7 +118,7 @@ class Model_Thor(Model):
             dataset.__loop_size__ = 1
         dataset_helper = DatasetHelper(dataset, dataset_sink_mode, sink_size, epoch_num, iter_first_order)
 
-        if dataset_sink_mode:
+        if dataset_sink_mode and context.get_context("device_target") != "GPU":
             network = connect_network_with_dataset(network, dataset_helper)
         network.set_train(is_train)
         network.phase = phase