Populate the supported interfaces bitmap for the Ocelot DSA switches.
Since all sub-drivers only support a single interface mode, defined by
ocelot_port->phy_mode, we can handle this in the main driver code
without reference to the sub-driver.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com> Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>