net: dsa: mv88e6xxx: Provide function for common port initialization
Provide mv88e6xxx_setup_port_common() for common port initialization.
Currently only write Port 1 Control and VLAN configuration since
this will be needed for hardware bridging. More can be added later
if desired/needed.
Reviewed-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: David S. Miller <davem@davemloft.net>