Fixed flash attention 2 crash in qwen vl and omni models
Author: petkokp
Pull request: yes

# What does this PR do?

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Fixes https://github.com/huggingface/transformers/issues/39095

The changes introduced by this refactoring are the reason for the issue https://github.com/huggingface/transformers/pull/38930

This appear reverts the refactoring.

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