fix split in image-segmentation config

rock-glacier-dataset.py

@@ -135,15 +135,7 @@ class RockGlacierDataset(datasets.GeneratorBasedBuilder):
           return splits 
            
        if self.config.name == "image-segmentation":
-          train_data = dl_manager.iter_files([data_files["train"]]), dl_manager.iter_files([data_files["train_mask"]])
-          return [
-             datasets.SplitGenerator(
-                name=datasets.Split.TRAIN,
-                gen_kwargs={
-                   "files": train_data,
-                   "split": "training",
-                },
-             )]
+          return splits
                 
 
    def _generate_examples(self, files, split):