Merge branch 'net-dsa-mv88e6xxx-add-88e6361-support'

Merge branch 'net-dsa-mv88e6xxx-add-88e6361-support'

Alexis Lothoré says:

====================
net: dsa: mv88e6xxx: add 88E6361 support

This series brings initial support for Marvell 88E6361 switch.

MV88E6361 is a 8 ports switch with 5 integrated Gigabit PHYs and 3
2.5Gigabit SerDes interfaces. It is in fact a new variant in the
88E639X/88E6193X/88E6191X family with a subset of existing features:
- port 0: MII, RMII, RGMII, 1000BaseX, 2500BaseX
- port 3 to 7: triple speed internal phys
- port 9 and 10: 1000BaseX, 25000BaseX

Since said family is already well supported in mv88e6xxx driver, adding
initial support for this new switch mostly consists in finding the ID
exposed in its identification register, adding a proper description
in switch description tables in mv88e6xxx driver, and enforcing 88E6361
specificities in mv88e6393x_XXX methods.

- first 4 commits introduce an internal phy offset field for switches which
  have internal phys but not starting from port 0
- 5th commit is a fix on existing switches based on first commits
- 6th commit is a slight modification to prepare 886361 support
- last commit introduces 88E6361 support in 88E6393X family

This initial support has been tested with two samples of a custom board
with the following hardware configuration:
- a main CPU connected to MV88E6361 using port 0 as CPU port
- port 9 wired to a SFP cage
- port 10 wired to a G.Hn transceiver

The following setup was used:
PC <-ethernet-> (copper SFP) - Board 1 - (G.hn) <-phone line(RJ11)-> (G.hn) Board 2

The unit 1 has been configured to bridge SFP port and G.hn port together,
which allowed to successfully ping Board 2 from PC.
====================

Link: https://lore.kernel.org/r/20230529080246.82953-1-alexis.lothore@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>