ath79: Add support for D-Link DIR-869-A1
Specifications
The D-Link EXO AC1750 (DIR-869) router released in 2016.
It is powered by Qualcomm Atheros QCA9563 @ 750 MHz chipset, 64 MB RAM and 16 MB flash.
10/100/1000 Gigabit Ethernet WAN port
Four 10/100/1000 Gigabit Ethernet LAN ports
Power Button, Reset Button, WPS Button, Mode Switch
Flashing
1. Upload factory.bin via D-link web interface (Management/Upgrade).
Revert to stock
Upload original firmware via OpenWrt sysupgrade interface.
Debricking
D-Link Recovery GUI (192.168.0.1)
Signed-off-by: Jan Forman <forman.jan96@gmail.com>