ramips: add support for MTS WG430223

ramips: add support for MTS WG430223

MTS WG430223 is a wireless AC1300 (WiFi 5) router manufactured by
Arcadyan company. It's very similar to Beeline Smartbox Flash (Arcadyan
WG443223).

Device specification
--------------------
SoC Type: MediaTek MT7621AT
RAM: 128 MiB
Flash: 128 MiB (Winbond W29N01HV)
Wireless 2.4 GHz (MT7615DN): b/g/n, 2x2
Wireless 5 GHz (MT7615DN): a/n/ac, 2x2
Ethernet: 3xGbE (WAN, LAN1, LAN2)
USB ports: No
Button: 1 (Reset/WPS)
LEDs: 2 (Red, Green)
Power: 12 VDC, 1 A
Connector type: Barrel
Bootloader: U-Boot (Ralink UBoot Version: 5.0.0.2)
OEM: Arcadyan WG430223

Installation
------------
1. Login to the router web interface (superadmin:serial number)
2. Navigate to Administration -> Miscellaneous -> Access control lists &
   enable telnet & enable "Remote control from any IP address"
3. Connect to the router using telnet (default admin:admin)
4. Place *factory.trx on any web server (192.168.1.2 in this example)
5. Connect to the router using telnet shell (no password required)
6. Save MAC adresses to U-Boot environment:
   uboot_env --set --name eth2macaddr --value $(ifconfig | grep eth2 | \
    awk '{print $5}')
   uboot_env --set --name eth3macaddr --value $(ifconfig | grep eth3 | \
    awk '{print $5}')
   uboot_env --set --name ra0macaddr --value $(ifconfig | grep ra0 | \
    awk '{print $5}')
   uboot_env --set --name rax0macaddr --value $(ifconfig | grep rax0 | \
    awk '{print $5}')
7. Ensure that MACs were saved correctly:
   uboot_env --get --name eth2macaddr
   uboot_env --get --name eth3macaddr
   uboot_env --get --name ra0macaddr
   uboot_env --get --name rax0macaddr
8. Download and write the OpenWrt images:
   cd /tmp
   wget http://192.168.1.2/factory.trx
   mtd_write erase /dev/mtd4
   mtd_write write factory.trx /dev/mtd4
9. Set 1st boot partition and reboot:
   uboot_env --set --name bootpartition --value 0

Back to Stock
-------------
1. Run in the OpenWrt shell:
   fw_setenv bootpartition 1
   reboot
2. Optional step. Upgrade the stock firmware with any version to
   overwrite the OpenWrt in Slot 1.

MAC addresses
-------------
+-----------+-------------------+----------------+
| Interface | MAC               | Source         |
+-----------+-------------------+----------------+
| label     | A4:xx:xx:51:xx:F4 | No MACs was    |
| LAN       | A4:xx:xx:51:xx:F6 | found on Flash |
| WAN       | A4:xx:xx:51:xx:F4 | [1]            |
| WLAN_2g   | A4:xx:xx:51:xx:F5 |                |
| WLAN_5g   | A6:xx:xx:21:xx:F5 |                |
+-----------+-------------------+----------------+
[1]:
a. Label wasb't found neither in factory nor in other places.
b. MAC addresses are stored in encrypted partition "glbcfg". Encryption
   key hasn't known yet. To ensure the correct MACs in OpenWrt, a hack
   with saving of the MACs to u-boot-env during the installation was
   applied.
c. Default Ralink ethernet MAC address (00:0C:43:28:80:A0) was found in
   "Factory" 0xfff0. It's the same for all MTS WG430223 devices. OEM
   firmware also uses this MAC when initialazes ethernet driver. In
   OpenWrt we use it only as internal GMAC (eth0), all other MACs are
   unique. Therefore, there is no any barriers to the operation of several
   MTS WG430223 devices even within the same broadcast domain.

Stock firmware image format
---------------------------
The same as Beeline Smartbox Flash but with another trx magic
+--------------+---------------+----------------------------------------+
| Offset       |               | Description                            |
+==============+===============+========================================+
| 0x0          | 31 52 48 53   | TRX magic "1RHS"                       |
+--------------+---------------+----------------------------------------+

Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
(cherry picked from commit 498c15376bae109bfe130cc5581f83e4cc52c0f9)