ARM: dts: armada-385-linksys: drop legacy DSA bindings

The new ones work so there is little reason to keep the legacy bindings.
Use the rework as the opportunity to drop the legacy node.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>