arm64: dts: marvell: espressobin: Simplify v7 ethernet port labeling

Now that the switch ports have a label in the .dtsi, simplify the whole
"switch0" block for the v7 dts files.

Signed-off-by: Andre Heider <a.heider@gmail.com>
Reviewed-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>