Alexandru Gagniuc authored Aug 20, 2022 and Sander Vanheule committed Sep 13, 2022

Add support for the TP-Link SG2210P switch. This is an RTL8380 based
switch with eight RJ-45 ports with 802.3af PoE, and two SFP ports.

This device shares the same board with the SG2008P and SG2008. To
model this, declare all the capabilities in the sg2xxx dtsi, and
disable unpopulated on the lower end models.

Specifications:
---------------
 - SoC:       Realtek RTL8380M
 - Flash:     32 MiB SPI flash (Vendor varies)
 - RAM:	      256 MiB (Vendor varies)
 - Ethernet:  8x 10/100/1000 Mbps with PoE (all ports)
              2x SFP ports
 - Buttons:   1x "Reset" button on front panel
 - Power:     53.5V DC barrel jack
 - UART:      1x serial header, unpopulated
 - PoE:       2x TI TPS23861 I2C PoE controller

Works:
------
  - (8) RJ-45 ethernet ports
  - (2) SFP ports (with caveats)
  - Switch functions
  - System LED

Not yet enabled:
----------------
  - Power-over-Ethernet (driver works, but doesn't enable "auto" mode)
  - PoE LEDs

Enabling SFP ports:
--------...