Add support for the SolidRun LX2162A System on Module (SoM), and the
Clearfog evaluation board.

The SoM has few software-controllable features:
- AR8035 Ethernet PHY
- eMMC
- SPI Flash
- fan controller
- various eeproms

The Clearfog evaluation board provides:
- microSD connector
- USB-A
- 2x 10Gbps SFP+
- 2x 25Gbps SFP+ with a retimer
- 8x 2.5Gbps RJ45
- 2x mPCI (assembly option / disables 2xRJ45)

The 8x RJ45 ports are connected with an 8-port PHY: Marvell 88E2580
supporting up to 5Gbps, while SoC and magnetics are limited to 2.5Gbps.

However 2500 speed is untested due to documentation and drivier
limitations. To avoid confusion the phy nodes have been explicitly
limited to 1000 for now.

The PCI nodes are disabled, but explicitly added to mark that this board
can have pci.
It is expected that the bootloader will patch the status property
"okay" and disable 2x RJ45 ports, according to active serdes configuration.
Signed-off-by: Josua Mayer <josua@solid-run.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>