Merge branch 'axienet-pcs-modernize'

Russell King says:

====================
net: axienet: modernise pcs implementation

These two patches modernise the Xilinx axienet PCS implementation to
use the phylink split PCS support.

The first patch adds split PCS support and makes use of the newly
introduced mac_select_pcs() function, which is the preferred way to
conditionally attach a PCS.

The second patch cleans up the use of mdiobus_write() since we now have
bus accessors for mdio devices.

There should be no functional change to the driver.

This series was previously sent CFT on the 16th December (message ID
Ybs1cdM3KUTsq4Vx@shell.armlinux.org.uk), and feedback addressed. CFT v2
sent 4th January (message ID YdQlI8gcVwg2sR+5@shell.armlinux.org.uk).
====================

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