Potential catastrophic error in xa_nn_vec_sigmoid_f32_f32 function

[Zhao-Dongyu]

I've encountered a significant issue with the xa_nn_vec_sigmoid_f32_f32 function. It seems to be corrupting data in other memory locations, leading to unexpected behavior in my application. I would greatly appreciate it if you could investigate the implementation of this function to identify and address the problem.

Additionally, I'm wondering if there's a better way to ensure issues are noticed and addressed. I haven't received any responses to previous issues I've raised.