That whistle noise is caused by water flowing through the pipes and the fill valve assembly. You can try to reduce that noise by slightly closing the cold water supply faucet behind the washer slightly. This may reduce the water flow supplied to the washer enough to reduce or eliminate that noise. Do not close that faucet too much or the washer will not fill properly and it will stop and display an error code.
If slightly closing that cold water faucet does not help, then you may not be able to reduce or eliminate it. If you have control over a water pressure regulator for your home, you may be able to reduce the noise by slightly reducing the house water pressure.
I hope that this information helps. If you need more assistance, reply with additional details.