[doc] `image_processing_vilt.py` wrong default documented
Sync the doc with reality.

https://github.com/huggingface/transformers/blob/ee4250a35f3bd5e9a4379b4907b3d8f9d5d9523f/src/transformers/models/vilt/image_processing_vilt.py#L299

https://github.com/huggingface/transformers/blob/ee4250a35f3bd5e9a4379b4907b3d8f9d5d9523f/src/transformers/models/vilt/image_processing_vilt.py#L310
_The documentation is not available anymore as the PR was closed or merged._