Merge branch 'net-Add-support-for-Synopsys-DesignWare-XPCS'

Jose Abreu says:

====================
net: Add support for Synopsys DesignWare XPCS

This adds support for Synopsys DesignWare XPCS in net subsystem and
integrates it into stmmac.

At 1/8, we start by removing the limitation of stmmac selftests that needed
a PHY to pass all the tests.

Then at 2/8 we use some helpers in stmmac so that some code can be
simplified.

At 3/8, we fallback to dev_fwnode() so that PCI based setups wich may
not have CONFIG_OF can still use FW node.

At 4/8, we adapt stmmac to the new PHYLINK changes as suggested by Russell
King.

We proceed by doing changes in PHYLINK in order to support XPCS: At 5/8 we
add some missing speeds that USXGMII supports and at 6/8 we check if
Autoneg is supported after initial parameters are validated.

Support for XPCS is finally introduced at 7/8, along with the usage of it
in stmmac driver at 8/8.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>