docs: Add instructions to install git lfs (#627)

examples/tensorrt_llm/README.md

@@ -50,6 +50,10 @@ See [here](https://nvidia.github.io/TensorRT-LLM/installation/linux.html) for mo
 Use the helper script to build a TensorRT-LLM container base image. The script uses a specific commit id from TensorRT-LLM main branch.
 
 ```bash
+# TensorRT-LLM uses git-lfs, which needs to be installed in advance.
+apt-get update && apt-get -y install git git-lfs
+git lfs install
+
 ./container/build_trtllm_base_image.sh
 ```