Merge branch 'Cadence-ZyncMP-SGMII'

Robert Hancock says:

====================
Cadence MACB/GEM support for ZynqMP SGMII

Changes to allow SGMII mode to work properly in the GEM driver on the
Xilinx ZynqMP platform.

Changes since v3:
-more code formatting and error handling fixes

Changes since v2:
-fixed missing includes in DT binding example
-fixed phy_init and phy_power_on error handling/cleanup, moved
phy_power_on to open rather than probe

Changes since v1:
-changed order of controller reset and PHY init as per suggestion
-switched device reset to be optional
-updated bindings doc patch for switch to YAML
====================

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