Chill guys, this is a normal and really common problem. Just a design flaw. The driver side mirror hits the wind in such a way that it makes this annoying whistling sound. I posted about it as well.
If you put your hand over the mirror cover you won't hear the noise.
A simple remedy is to take some electrical tape and cover the little slit on the mirror cover, which is where the problem initially arises. However, it'll look sorta rice, lol.