Remove check as nncf now a required dependency

[echarlaix]

nncf added in openvino extra in #586

cc @helena-intel @eaidova

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[helena-intel]

NNCF is a standard dependency in the [openvino] extra now, but from my perspective that doesn't make it a "required dependency". You can still use optimum-intel without NNCF. It's a pretty common use-case for me to convert models offline and then in the inference environment just do pip install optimum-intel openvino.

[EDIT] I see that with optimum-intel from source NNCF is already required just for importing . That is unexpected to me. I mentioned in the linked PR too that there was still a method to install without NNCF.

[echarlaix]

NNCF is a standard dependency in the [openvino] extra now, but from my perspective that doesn't make it a "required dependency". You can still use optimum-intel without NNCF. It's a pretty common use-case for me to convert models offline and then in the inference environment just do pip install optimum-intel openvino.

[EDIT] I see that with optimum-intel from source NNCF is already required just for importing . That is unexpected to me. I mentioned in the linked PR too that there was still a method to install without NNCF.

Yes it's the case since #638, added a fix in #668 in case we don't want to merge this PR (and make nncf officially a required dependency)