Merge branch 'net-dsa-mv88e6xxx-serdes-link-without-phy'

Merge branch 'net-dsa-mv88e6xxx-serdes-link-without-phy'

Chris Packham says:

====================
net: dsa: mv88e6xxx: serdes link without phy

This small series gets my hardware into a working state. The key points are to
make sure we don't force the link and that we ask the MAC for the link status.
I also have updated my dts to say `phy-mode = "1000base-x";` and `managed =
"in-band-status";`

I've dropped the patch for the 88E6123 as it's a distraction and I lack
hardware to do any proper testing with it. Earlier versions are on the mailing
list if anyone wants to pick it up in the future.

I notice there's a series for mv88e6393x circulating on the netdev mailing
list. As patch #1 is adding a new device specific op either this series will
need updating to cover the mv88e6393x or the mv88e6393x series will need
updating for the new op depenting on which lands first.
====================

Link: https://lore.kernel.org/r/20201124043440.28400-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Jakub Kicinski <kuba@kernel.org>