Fix AttributeError in fixed_sub_image_list for embedding models

[majunpo]

What does this PR do?

This PR fixes an AttributeError in fixed_sub_image_list when running
non-vision models such as BertEmbeddingModel.

Previously, the function assumed model.config always exists, which
causes:
AttributeError: 'BertEmbeddingModel' object has no attribute 'config'

What is changed?

• Add a defensive check using hasattr(model, "config")
• Only apply the DeepSeek OCR specific logic when model.config.model_type == "deepseek_ocr"

Impact

• No behavior change for deepseek_ocr models
• Improves robustness for embedding / non-vision models
• Safe for existing HPU inference paths