arm: dts: marvell: clearfog-gtr-l8: add support for second sfp connector

Clearfog GTR L8 has an extra SFP connector on the managed switch port 9.
Add descriptions for both entities along with pinctrl.

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