net: ethernet: fec: Allow configuration of MDIO bus speed
MDIO busses typically operate at 2.5MHz. However many devices can operate at faster speeds. This then allows more MDIO transactions per second, useful for Ethernet switch statistics, or Ethernet PHY TDR data. Allow the bus speed to be configured, using the standard "clock-frequency" property, which i2c busses use to indicate the bus speed. Before using this property, ensure all devices on the bus do actually support the requested clock speed. Suggested-by: Chris Healy <Chris.Healy@zii.aero> Signed-off-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>