Enable multi-device for efficientnet

[jla524]

What does this PR do?

Fixes #29786 (issue)

Tested on two systems, one with 2x RTX 3060 and one with 2x RTX 3090

$ pytest tests/models/efficientnet/test_modeling_efficientnet.py -k "parallel or offload"
=================================================================== test session starts ===================================================================
platform linux -- Python 3.10.13, pytest-7.4.4, pluggy-1.4.0
rootdir: /repos/transformers
configfile: pyproject.toml
plugins: hypothesis-6.98.10, xdist-3.5.0, timeout-2.3.1, anyio-4.3.0
collected 108 items / 101 deselected / 7 selected                                                                                                         

tests/models/efficientnet/test_modeling_efficientnet.py .......                                                                                     [100%]

<warnings redacted>
===================================================== 7 passed, 101 deselected, 12 warnings in 8.85s ======================================================

Who can review?

@amyeroberts

[ArthurZucker]

Suggested change

	_no_split_modules = []
	_no_split_modules = ["EfficientNetBlock"]

any reason not to set a correct module to not split?

[amyeroberts]

@ArthurZucker I don't think it's necessary for there to be a module defined - this is the case for some of our models already in the library e.g. Camembert.

It is strange not defining "EfficientNetBlock" is OK though, as the block uses a residual connection, which requires the two tensors to be on the same device (as then so too the weights).

[ArthurZucker]

Alright, it's not necessary, but for small GPU it helps. We'll see how it goes