arm64: dts: add support for SolidRun Clearfog GT 8K

arm64: dts: add support for SolidRun Clearfog GT 8K

The SolidRun Clearfog GT-8K is based on Marvell Armada 8040 SoC.

  https://wiki.solid-run.com/doku.php?id=products:a8040:clearfoggt8k

The following devices were tested with this DT on top of kernel
v4.19-rc4:

  * 1GB Ethernet WAN

  * 4 ports 1GB Ethernet switch (2.5GB uplink)

  * SFP port

  * SATA on CON3 PCIe slot

  * USB3 type A port

  * SD card and eMMC

  * 2 LEDs

  * 2 push buttons

[gregory: fix block comment alignement]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>