LFM2 (#39340)

* [modeling][lfm2] LFM2 model on 4.53.0 interface

* [configuration] hook in LFM2 keys

* [modeling][lfm2] update modeling interface for 4.53.1

* [modeling][lfm2] apply mask to hidden conv states

* [misc] ruff format/lint

* [modeling][lfm2] minor: NotImplemented legacy cache conversion

* Create lfm2.md

* create nice modular

* style

* Update modeling_auto.py

* clean and start adding tests

* style

* Update test_modeling_lfm2.py

* Update __init__.py

* small test model size

* config

* small fix

* fix

* remove useless config attrs -> block_dim and conv_dim are hiden_size

* fix prepare inputs

* fix config

* test

* typo

* skip tests accordingly

* config docstrings

* add doc to .md

* skip config docstring check

---------

Co-authored-by: Maxime Labonne <81252890+mlabonne@users.noreply.github.com>
Co-authored-by: Cyril Vallez <cyril.vallez@gmail.com>

tests/generation/test_utils.py

@@ -2503,6 +2503,7 @@ class GenerationTesterMixin:
             "xlnet",
             "zamba",
             "zamba2",
+            "lfm2",
         )
         has_standard_cache = not any(
             model_name in config.__class__.__name__.lower() for model_name in models_without_standard_cache