remove base_model metadata

Current metadata causes
```
Unable to build the model tree, the base model loops to the model itself. Learn more.
```

https://huggingface.co/docs/hub/model-cards#specifying-a-base-model for more info

README.md

@@ -12,7 +12,6 @@ language:
 - pt
 - sv
 - da
-base_model: lightonai/LightOnOCR-1B-1025
 library_name: vllm
 tags:
 - ocr