Merge branch 'davinci_mdio'

Grygorii Strashko says:

====================
net: davinci_mdio: reuse for keystone2 arch

The similar MDIO HW blocks is used by keystone 2 SoCs as
in Davinci SoCs:
- one in Gigabit Ethernet (GbE) Switch Subsystem
  See http://www.ti.com/lit/ug/sprugv9d/sprugv9d.pdf
- one in 10 Gigabit Ethernet Subsystem
  See http://www.ti.com/lit/ug/spruhj5/spruhj5.pdf

Hence, reuse Davinci MDIO driver for Keystone 2 and
enable TI networking for Keystone 2 devices.

Also, as part of this series, enable PHY's creation from DT, because
Keystone 2 supports DT boot mode only.

Changes in v2:
- review comments applied.
  Keystone 2 compatibility string changed to "ti,keystone_mdio".
====================

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