arm: dts: marvell: clearfog-gtr-l8: align port numbers with enclosure

Clearfog GTR has an official enclosure with labels for all interfaces.
The "lan" ports on the 8-port switch in device-tree were numbered  in
reverse wrt. enclosure.

Update all device-tree labels to match.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>