Merge branch 'ksz886x-cable-test'

Oleksij Rempel says:

====================
provide cable test support for the ksz886x switch

changes v5:
- drop resume() patch
- add Reviewed-by tags.
- rework dsa_slave_phy_connect() patch

changes v4:
- use fallthrough;
- use EOPNOTSUPP instead of ENOTSUPP
- drop flags variable in dsa_slave_phy_connect patch
- extend description for the "net: phy: micrel: apply resume errat"
  patch
- fix "use consistent alignments" patch

changes v3:
- remove RFC tag

changes v2:
- use generic MII_* defines where possible
- rework phylink validate
- remove phylink get state function
- reorder cabletest patches to make PHY flag patch in the right order
- fix MDI-X detection

This patches provide support for cable testing on the ksz886x switches.
Since it has one special port, we needed to add phylink with validation
and extra quirk for the PHY to signal, that one port will not provide
valid cable testing reports.
====================

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