Merge branch 'net-dsa-qca8k-Improve-SGMII-interface-handling'

Jonathan McDowell says:

====================
net: dsa: qca8k: Improve SGMII interface handling

This 3 patch series migrates the qca8k switch driver over to PHYLINK,
and then adds the SGMII clean-ups (i.e. the missing initialisation) on
top of that as a second patch. The final patch is a simple spelling fix
in a comment.

As before, tested with a device where the CPU connection is RGMII (i.e.
the common current use case) + one where the CPU connection is SGMII. I
don't have any devices where the SGMII interface is brought out to
something other than the CPU.

v5:
- Move spelling fix to separate patch
- Use ds directly rather than ds->priv
v4:
- Enable pcs_poll so we keep phylink updated when doing in-band
  negotiation
- Explicitly check for PHY_INTERFACE_MODE_1000BASEX when setting SGMII
  port mode.
- Address Vladimir's review comments
v3:
- Move phylink changes to separate patch
- Address rmk review comments
v2:
- Switch to phylink
- Avoid need for device tree configuration options
====================

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