qualcommax: add support for Aliyun AP8220

qualcommax: add support for Aliyun AP8220

Aliyun AP8220 is an AP manufactured by Edgecore.
(Very similar to Edgecore EAP102)

Hardware specifications:
  SoC: Qualcomm IPQ8071A
  RAM: 1GB of DDR4 600MHz
  Flash1: MX25U3235F 4MB
  Flash2: MX30UF1G18AC 128MB
  Ethernet: 2x 2.5G RJ45 port
  USB: 2x USB-A 2.0 port
  WiFi1: QCN5024 2.4GHz
  WiFi2: QCN5054 5GHz
  Power: DC 12V / PoE

Flash instructions:
  1. Connect the router via serial port
  2. Keep pressing @ until uboot is interrupted
  3. Download the initramfs image, rename it to
     initramfs.bin, host it with tftp server
  4. Run these commands:
     tftpboot initramfs.bin
     bootm
  5. After openwrt boots up, use scp or luci
     to upload sysupgrade.bin to upgrade.

Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
Link: https://github.com/openwrt/openwrt/pull/17970
Signed-off-by: Robert Marko <robimarko@gmail.com>