arm64: dts: a7k: add COM Express boards

arm64: dts: a7k: add COM Express boards

Add support for Armada 7020 Express Type 7 CPU module board by Marvell.
Define this COM Express CPU module as dtsi and provide a dtsi file for
the carrier board (Marvell DB-98CX85x0 COM Express type 7 carrier board).

Since memory is soldered on CPU module, memory node is on CPU module
dtsi file.

This Carrier board only utilizes the PCIe link, hence no special device
or driver support is provided by this dtsi file.
Devise a dts file for the combined com express carrier and CPU module.

The Aramda 7020 CPU COM Express board offers the following features:

1.  Armada 7020 CPU, with dual ARM A72 cores
2.  DDR4 memory, 8GB, on board soldered
3.  1Gbit Out of Band Ethernet via RGMII to PHY and RJ45 connector,
    all are present on A7K CPU module (none on the carrier)
4.  Optional 10G KR Ethernet going via the COM Express type 7 connector
5.  On-board 8 Gbit, 8-bit bus width NAND flash
6.  On-board 512 Mbit SPI flash
7.  PCIe Root Complex, 4 lanes PCIe gen3 connectivity, going via the
    COM Express type 7 connector
8.  m.2 SATA connector
9.  Micro-SD card connector
10. USB 2.0 via COM Express type 7 connector
11. Two i2c interfaces - one to the CPU module, and one to the
    carrier board via the COM Express type 7 connector
12. UART (mini USB connector by virtue of FT2232D UART to USB
    converter, connected to the Armada 7020 UART0)

gc: 10gbase-kr is legacy, use "10gbase-r" instead in cp0_eth0 node
Signed-off-by: Elad Nachman <enachman@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>