Add support for WPA/WPA2 when running in DSi mode

[DaMatrix]

The title should be self-explanatory, supporting WPA/WPA2 in DSi mode would in theory be possible using the already functional code in nocash's wifiboot.

I don't know enough about the internals of the DS(i) yet to be able to implement this myself, but I'm willing to help in any way that I can.

[fincs]

nocash's DS(i) software doesn't use any of the preexisting homebrew infrastructure, not even libnds (let alone dswifi). Adding Atheros Wifi support would entail writing an entirely new driver from scratch since nocash's code cannot really be used under our infrastructure. On top of that, dswifi is in dire need of a complete rewrite due to several historical reasons.

[DaMatrix]

let's make this happen

[fincs]

DSi Atheros Wi-Fi with WPA/WPA2-AES-PSK support is now a reality.