Fix TF CTRL model naming
This PR fixes an issue with the naming of some layers in the TensorFlow version of CTRL.
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=h1) Report
> Merging [#6134](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/641b873c1341f553b40fd82c990b80884b585f0b&el=desc) will **decrease** coverage by `0.00%`.
> The diff coverage is `100.00%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/6134/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #6134      +/-   ##
==========================================
- Coverage   78.64%   78.63%   -0.01%     
==========================================
  Files         146      146              
  Lines       26326    26333       +7     
==========================================
+ Hits        20704    20708       +4     
- Misses       5622     5625       +3     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_tf\_ctrl.py](https://codecov.io/gh/huggingface/transformers/pull/6134/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9jdHJsLnB5) | `97.84% <100.00%> (+0.05%)` | :arrow_up: |
| [src/transformers/generation\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6134/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9nZW5lcmF0aW9uX3RmX3V0aWxzLnB5) | `83.20% <0.00%> (-2.51%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6134/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `83.44% <0.00%> (-0.65%)` | :arrow_down: |
| [src/transformers/tokenization\_xlm\_roberta.py](https://codecov.io/gh/huggingface/transformers/pull/6134/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25feGxtX3JvYmVydGEucHk=) | `95.23% <0.00%> (+10.71%)` | :arrow_up: |

------

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> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=footer). Last update [641b873...1bc31c0](https://codecov.io/gh/huggingface/transformers/pull/6134?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
