mediatek: filogic: add support for ZBT-Z8803BE

mediatek: filogic: add support for ZBT-Z8803BE

Specifications:

SoC: MediaTek MT7988A (4 cores)
RAM: 1024MiB
Flash: Winbond SPI-NAND 128 MiB
Network: 1 WAN (2.5G), 3 LAN (1G), 1 SFP+ (10G)
2 SIM slots
Buttons: Reset, WPS
Power: DC 12V 3A (Recommend 19V to avoid voltage drop)
WiFi: MT7996 2.4Ghz, 5.8Ghz and 6Ghz (BE19000)
    - 2.4Ghz and 5.8Ghz share same dual band antenna (4)
    - 6Ghz uses dedicated 6G antenna (4)
Misc: 1 USB2.0 port, UART header

Installation:

A. Through U-Boot menu:

  - Prepare your connecting computer to use a static IP in
    network 192.168.1.0/24
  - Power down the router and hold in the Reset button.
  - While holding in the button power up the router again.
  - Hold the button in for 10 seconds and then release.
  - Use your browser to go to 192.168.1.1
  - If you see a GUI allowing for flashing firmware then
    you got the right model.
  - Upload the sysupgrade file.

Note 1: Recovery GUI can be used to recover from an incorrect
      firmware flash.
Note 2: There is a GPIO watchdog that expires after 2 minutes
      so flashing sysupgrade via U-boot needs to be done
      quickly within that timer.

B. Through OpenWrt Dashboard:
  If your router comes with OpenWrt preinstalled
  (modified by the seller), you can easily upgrade
  by going to the dashboard (192.168.1.1) and then
  navigate to System -> Backup/Flash firmware,
  then flash the firmware

MAC Addresses:
LAN(printed MAC) : F8:5E:3C:xx:xx:xx (Factory, 0xffff4)
WAN              : F8:5E:3C:xx:xx:xx (Factory, 0xffffa)
SFP+             : F8:5E:3C:xx:xx:xx (Factory, 0xfffee)
2.4GHz           : F8:5E:3C:xx:xx:xx (Factory, 0x4)
5GHz             : F8:5E:3C:xx:xx:xx (Factory, 0x4) + 0x10
6Ghz             : F8:5E:3C:xx:xx:xx (Factory, 0x4) + 0x20

Signed-off-by: Tuan Phan <pttuan@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23053
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>