Merge branch 'phylink-dsa-prep'

Florian Fainelli says:

====================
PHYLINK preparatory patches for DSA

In preparation for having DSA migrate to PHYLINK, I had to come up with a
number of preparatory patches:

- we need to be able to pass phy_flags from an external component calling
  phylink_of_phy_connect()
- DSA tries to connect through OF first, then fallsback using its own internal
  MDIO bus, in that case we would both show an error, but also not know what
  the correct phy_interface_t would be, instead use the PHY device/driver provided
  one
- Finally bcm_sf2 makes use of all possible PHYs out there: internal, external,
  fixed, and MoCA, the latter requires a bit of help to signal link notifications
  through a MMIO interrupt, as well a report a correct PORT type

Changes in v2:

- rebased against latest net-next/master
- added kernel doc documentation
- dropped error message in phylink_of_phy_connect() as suggested by Russell
====================

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