Merge branch 'net-ethernet-mediatek-convert-to-PHYLINK'

René van Dorst says:

====================
net: ethernet: mediatek: convert to PHYLINK

These patches converts mediatek driver to PHYLINK API.

v3->v4:
* Phylink improvements and clean-ups after review
v2->v3:
* Phylink improvements and clean-ups after review
v1->v2:
* Rebase for mt76x8 changes
* Phylink improvements and clean-ups after review
* SGMII port doesn't support 2.5Gbit in SGMII mode only in BASE-X mode.
  Refactor the code.
====================

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