net: dsa: sja1105: determine PHY/MAC role from PHY interface type

Now that both RevMII as well as RevRMII exist, we can deprecate the
sja1105,role-mac and sja1105,role-phy properties and simply let the user
select that a port operates in MII PHY role by using
	phy-mode = "rev-mii";
or in RMII PHY role by using
	phy-mode = "rev-rmii";

There are no fixed-link MII or RMII properties in mainline device trees,
and the setup itself is fairly uncommon, so there shouldn't be risks of
breaking compatibility.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>