Merge branch 'genphy_read_abilities'

Heiner Kallweit says:

====================
net: phy: add and use new function genphy_read_abilities

Similar to genphy_c45_pma_read_abilities() add a function to dynamically
detect the abilities of a Clause 22 PHY. This is mainly copied from
genphy_config_init(). Main benefit is that PHY drivers no longer have
to specify whether they support GBit or not (provided they keep to
the C22 standard).
====================

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