dt-bindings: marvell: a38x: add solidrun armada 385 clearfog gtr boards

Add DT compatible for SolidRun Armada-385 based Clearfog GTR L8 and S4
boards.

Despite similar name these two boards are designed differently from the
armada 388 clearfog base and pro, they only share a name and general use
case.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>