Add rtl8812au-au driver

For devices like "Netis WF2190" Turris OS updater-drivers tries to install rtl8812au-ct driver which is not working correctly according to OpenWrt forum [0] and [1].

The solution could be to add a new driver rtl8812au-ac from https://github.com/1Jeff1/openwrt/commit/af426db0e78c3880a6bfe26fa97ae03caccce783. This should be first sent to OpenWrt upstream.

• [0] https://forum.openwrt.org/t/rtl8812au-and-or-rtl8814au-drivers/67/121
• [1] https://forum.openwrt.org/t/rtl8812au-and-or-rtl8814au-drivers/67/121