realtek: rtl931x: add support for Hasivo F5800W-12S+

realtek: rtl931x: add support for Hasivo F5800W-12S+

This commit adds support for the Hasivo F5800W-12S+ 12-port SFP+ switch.
Based on board revision `RTL_12S+ v1.01`.

Hardware
--------

|          |                                                                |
|----------|----------------------------------------------------------------|
| SoC      | RTL9313 rev B                                                  |
| RAM      | 512 MB Samsung K4B4G1646E                                      |
| Flash    | 32 MB Macronix MX25L25645G SPI NOR, 29 MB usable by OpenWrt    |
| Ethernet | 12x SFP+ via SoC (10G/2.5G/1G)                                 |
| LEDs     | 12x green 10G link, 12x green 1G link,                         |
|          | 3x green power and PSUs -- no system status LED                |
| Button   | Reset                                                          |
| Console  | RJ45 38400 bps 8n1                                             |
| Watchdog | via Hasivo MCU                                                 |
| Power    | 2x internal 100-240V AC PSUs with 2x C14 inputs                |
| Clock    | NXP PCF8563 with coin cell battery                             |
| Fans     | 2x 40mm case fan via Hasivo MCU                                |

Installing OpenWrt
------------------

1. Attach to RJ45 serial console port using a cisco cable.
2. Attach SFP to port 12.
3. Serve initramfs-kernel.bin on TFTP 192.168.1.111.
4. Power on the device.
5. Interrupt U-Boot by pressing `Ctrl+c`, then `z`, then `h`, during 3 second countdown.
6. Bring up networking: `rtk network on ; rtk 10g 55 fiber10g`.
7. Boot from TFTP: `tftpboot 0x84f00000 initramfs-kernel.bin ; bootm 0x84f00000`.
8. Use `mtd dump` to make backups of all flash partitions.
9. Use SCP to copy `squashfs-sysupgrade.bin` to the device, then run `sysupgrade`.

Restoring factory firmware
--------------------------

OpenWrt uses the `RUNTIME` and `RUNTIME2` partitions as one combined partition.
To restore them from backups, boot from `initramfs-kernel.bin` just like during
the installation, then use `mtd write` to write your backups of the factory
`mtd5` and `mtd6` partitions to the live `mtd5` partition.

Notes/Quirks
------------

- U-Boot interruption is obfuscated. Press `Ctrl+c`, then `z`, then `h`,
  during the 3 second countdown.
- MAC address is stored on the `RUNTIME` or `RUNTIME2` partitions,
  which are used by OpenWrt. Instead, we generate one random MAC address
  and store it in the U-Boot environment.
- There is no system status LED. The three non-network LEDs are for
  primary PSU (MS label), secondary PSU (SL), and powered on/off (PW).

Signed-off-by: Lars Gierth <larsg@systemli.org>
Link: https://github.com/openwrt/openwrt/pull/23443
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>