Add support for Dovado tiny AC wifi router.

Soc: mt7620a
ram: 64MB
flash: 8MB
1x usb 2.0
two gigabit lan ports

5ghz wlan is not supported on this board since there is no gpl driverfor mt7610e wifi chip.

Signed-off-by: Andrej Vlasic <andrej.vlasic0@gmail.com>

SVN-Revision: 47348