Merge branch 'net-add-phylink-support-for-PCS'

Russell King says:

====================
net: add phylink support for PCS

This series adds support for IEEE 802.3 register set compliant PCS
for phylink.  In order to do this, we:

1. convert BUG_ON() in existing accessors to WARN_ON_ONCE() and return
   an error.
2. add accessors for modifying a MDIO device register, and use them in
   phylib, rather than duplicating the code from phylib.
3. add support for decoding the advertisement from clause 22 compatible
   register sets for clause 37 advertisements and SGMII advertisements.
4. add support for clause 45 register sets for 10GBASE-R PCS.

These have been tested on the LX2160A Clearfog-CX platform.

v2: eliminate use of BUG_ON() in the accessors.
====================

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