Accept tensorflow-rocm package when checking TF availability
When working [on AMD GPU:s the TensorFlow package is called `tensorflow-rocm`](https://rocmdocs.amd.com/en/latest/Deep_learning/Deep-learning.html#tensorflow). This trivial PR just adds that to the list of accepted package names when checking for TensorFlow availability in `src/transformers/file_utils.py`.

At least the basic benchmark `run_benchmark_tf.py` seems to work fine on AMD MI50 and MI100 GPUs