realtek: support Teltonika TSW202

realtek: support Teltonika TSW202

Add support for TSW202 PoE switch. This is an RTL8380 based switch
with two SFP slots, and 8 PoE 802.3af one every RJ-45 port.

The max budget is 240W.
The vendor firmware configures the PSE
with a per-port budget of 30.0W.

Specifications:
---------------
* SoC:       Realtek RTL8380M
* Flash:     16 MiB SPI NOR W25Q80RV, 8Mb_Serial_Flash, low_power
* RAM:       128 MiB Winbond W631GG8NB 151
* Ethernet:  8x 10/100/1000 Mbps with PoE
             2x SFP slots
* Buttons:   1 "Reset" button on front panel
* Power:     48V-54V DC barrel jack
* UART:      1 serial header with terminal on the back side.
             With ground, rx, tx, and 3.3V
* PoE:       2 XS2184
* LED:       2 i2c SL74HC164

Works:
------
  - (8) RJ-45 ethernet ports
  - (2) SFP with ethernet or fiber
  - Switch functions

TODO:
------
  - LEDs are always on
  - Power-over-Ethernet are always on

Install via web interface:
-------------------------

The openwrt firmware will not accept and flash the sysupgrade image.

It is recommended to flash with sysupgrade -n -f over ssh.

Dokumantation, Bootlogs, and Fotos can be found on

https://git.f2a.space/patrick/openwrt-24.10-tsw202/-/wikis/home

Signed-off-by: Patrick Grimm <patrick@lunatiki.de>
Link: https://github.com/openwrt/openwrt/pull/21003
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>