Support for TL-WR840N(ES) Ver 5.0 (EU)

Actually just managed to flash sysupgrade image through WEB UI.
It booted, WAN and LAN work.
WLAN needs testing.
MAC address is read correctly, gotta check if radio calibration data location is correct.
There is only one LED and it uses green as default in bootloader and stock uses orange when booted, gotta look into that.