MIPS: configs: CI20: Enable WiFi / Bluetooth

Enable the required drivers for the WiFi / Bluetooth functionality.

I enabled WEXT compatibility as well since the CI20 is typically used
with a very old userspace.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>