Fix the requires_grad adjustment logic in mark_only_lora_as_trainable

[MikuAndRabbit]

Added code to the mark_only_lora_as_trainable method to set requires_grad to True for parameters with lora_ in the name.

This change was made for the following reason.

Sometimes requires_grad may be set to False for all parameters of the whole model before calling the mark_only_lora_as_trainable method, and if following the logic of the existing mark_only_lora_as_trainable method, the requires_grad of the parameter whose name contains lora_ is still set to False after calling, which I think has some conflict with the method name mark_only_lora_as_trainable.